2013_CSUST_3_23校内训练赛第一场【old】【hdu 3496、2191、4508、4506、2181 POJ 3264 3210 3094】

                                         训练赛(Older)#001

题解(F):

1不知道  二维多重背包。。。
2多重背包模板题
3完全背包模板题
4线段树求区间最值 模板题
5幂取模乱搞 
6DFS
7水题
8水题

    ID Origin Title
  2 / 14 Problem A HDU 3496 Watch The Movie
10 / 23 Problem B HDU 2191 悼念512汶川大地震遇难同胞――珍惜现在,感恩生活
8 / 11 Problem C HDU 4508 湫湫系列故事――减肥记I
  5 / 9 Problem D POJ 3264 Balanced Lineup
6 / 22 Problem E HDU 4506 小明系列故事――师兄帮帮忙
  4 / 5 Problem F HDU 2181 哈密顿绕行世界问题
  4 / 6 Problem G POJ 3210 Coins
7 / 7 Problem H POJ 3094 Quicksum


B

悼念512汶川大地震遇难同胞——珍惜现在,感恩生活

Time Limit: 1000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 8868    Accepted Submission(s): 3719


Problem Description
急!灾区的食物依然短缺!
为了挽救灾区同胞的生命,心系灾区同胞的你准备自己采购一些粮食支援灾区,现在假设你一共有资金n元,而市场有m种大米,每种大米都是袋装产品,其价格不等,并且只能整袋购买。
请问:你用有限的资金最多能采购多少公斤粮食呢?

后记:
人生是一个充满了变数的生命过程,天灾、人祸、病痛是我们生命历程中不可预知的威胁。
月有阴晴圆缺,人有旦夕祸福,未来对于我们而言是一个未知数。那么,我们要做的就应该是珍惜现在,感恩生活——
感谢父母,他们给予我们生命,抚养我们成人;
感谢老师,他们授给我们知识,教我们做人
感谢朋友,他们让我们感受到世界的温暖;
感谢对手,他们令我们不断进取、努力。 
同样,我们也要感谢痛苦与艰辛带给我们的财富~

2013_CSUST_3_23校内训练赛第一场【old】【hdu 3496、2191、4508、4506、2181 POJ 3264 3210 3094】_第1张图片
 

Input
输入数据首先包含一个正整数C,表示有C组测试用例,每组测试用例的第一行是两个整数n和m(1<=n<=100, 1<=m<=100),分别表示经费的金额和大米的种类,然后是m行数据,每行包含3个数p,h和c(1<=p<=20,1<=h<=200,1<=c<=20),分别表示每袋的价格、每袋的重量以及对应种类大米的袋数。
 

Output
对于每组测试数据,请输出能够购买大米的最多重量,你可以假设经费买不光所有的大米,并且经费你可以不用完。每个实例的输出占一行。
 

Sample Input
   
   
   
   
1 8 2 2 100 4 4 100 2
 

Sample Output
   
   
   
   
400
 

Author
lcy
 

Source
2008-06-18《 ACM程序设计》期末考试——四川加油!中国加油!
 

Recommend
lcy

思路:多重背包模板题

转换为01背包思想

procedure MultiplePack(cost,weight,amount)

    if cost*amount>=V

        CompletePack(cost,weight)

        return

    integer k=1

    while k<num

        ZeroOnePack(k*cost,k*weight)

        amount=amount-k

        k=k*2

    ZeroOnePack(amount*cost,amount*weight)


#include<cstdio>
#include<cstring>
#include<algorithm>
#include<cmath>
using namespace std;

const int maxn = 110;
const int Maxn = 20*100+10;
int dp[maxn];
int n,m;
int N;
int v[Maxn],w[Maxn];

struct Node{
	int v,w,c;
}t[maxn];

int main()
{
	int a,b,e;
	int T;
	int n,m;
	scanf("%d",&T);
	while(T--)
	{
		int N = 0;
		memset(dp,0,sizeof(dp));
		scanf("%d%d", &n, &m);
		for(int i = 0; i < m; i++)
		{
			scanf("%d%d%d", &a, &b,&e);
			t[i].v=a;
			t[i].w=b;
			t[i].c=e;
			N+=e;
		}
		
		int k = 0;
		int s= 0;
		for(int i = 0; i < m; i++)
		{
		    k = 1;
			while(k<20 && t[i].c >= k)
			{
				v[s] = t[i].v*k;
				w[s++] = t[i].w*k;
				t[i].c -= k;
				k = k*2;
			} 
            v[s] = t[i].v*t[i].c;
	        w[s++] = t[i].w*t[i].c;	
		}
		
		
		for(int i = 0; i < s; i++)
		{
			for(int j = n; j >= v[i]; j--)
			dp[j] = max(dp[j], dp[j-v[i]]+w[i]);
		}
		printf("%d\n", dp[n]);
	}
	return 0;
}


C

湫湫系列故事——减肥记I

Time Limit: 3000/1000 MS (Java/Others)    Memory Limit: 65535/32768 K (Java/Others)
Total Submission(s): 922    Accepted Submission(s): 454


Problem Description
  对于吃货来说,过年最幸福的事就是吃了,没有之一!
  但是对于女生来说,卡路里(热量)是天敌啊!
  资深美女湫湫深谙“胖来如山倒,胖去如抽丝”的道理,所以她希望你能帮忙制定一个食谱,能使她吃得开心的同时,不会制造太多的天敌。

  当然,为了方便你制作食谱,湫湫给了你每日食物清单,上面描述了当天她想吃的每种食物能带给她的幸福程度,以及会增加的卡路里量。
 

Input
  输入包含多组测试用例。
  每组数据以一个整数n开始,表示每天的食物清单有n种食物。 
  接下来n行,每行两个整数a和b,其中a表示这种食物可以带给湫湫的幸福值(数值越大,越幸福),b表示湫湫吃这种食物会吸收的卡路里量。
  最后是一个整数m,表示湫湫一天吸收的卡路里不能超过m。

   [Technical Specification]
  1. 1 <= n <= 100
  2. 0 <= a,b <= 100000
  3. 1 <= m <= 100000
 

Output
  对每份清单,输出一个整数,即满足卡路里吸收量的同时,湫湫可获得的最大幸福值。
 

Sample Input
   
   
   
   
3 3 3 7 7 9 9 10 5 1 1 5 3 10 3 6 8 7 5 6
 

Sample Output
   
   
   
   
10 20
 

Source
2013腾讯编程马拉松初赛第一场(3月21日)
 

Recommend
liuyiding

思路:完全背包模板题

procedure CompletePack(cost,weight)

    for v=cost..V

        f[v]=max{f[v],f[v-c[i]]+w[i]}


#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
const int maxn = 100000+10;

int dp[maxn];
int w[110],v[110];
int n,m;

int main()
{
	while(scanf("%d", &n) != EOF)
	{
		memset(dp,0,sizeof(dp));
		//int a,b;
		for(int i = 0; i < n; i++)
		{
			scanf("%d%d", &w[i], &v[i]);
		}
		scanf("%d", &m);
		for(int i = 0; i < n; i++)
		{
			for(int j = v[i]; j <=m;  j++)
				dp[j] = max(dp[j], dp[j-v[i]]+w[i]);
		}
		printf("%d\n", dp[m]);
	}
	return 0;
}


D

Balanced Lineup
Time Limit: 5000MS   Memory Limit: 65536K
Total Submissions: 26485   Accepted: 12426
Case Time Limit: 2000MS

Description

For the daily milking, Farmer John's N cows (1 ≤ N ≤ 50,000) always line up in the same order. One day Farmer John decides to organize a game of Ultimate Frisbee with some of the cows. To keep things simple, he will take a contiguous range of cows from the milking lineup to play the game. However, for all the cows to have fun they should not differ too much in height.

Farmer John has made a list of Q (1 ≤ Q ≤ 200,000) potential groups of cows and their heights (1 ≤ height ≤ 1,000,000). For each group, he wants your help to determine the difference in height between the shortest and the tallest cow in the group.

Input

Line 1: Two space-separated integers,  N and  Q
Lines 2.. N+1: Line  i+1 contains a single integer that is the height of cow  i 
Lines  N+2.. N+ Q+1: Two integers  A and  B (1 ≤  A ≤  B ≤  N), representing the range of cows from  A to  B inclusive.

Output

Lines 1.. Q: Each line contains a single integer that is a response to a reply and indicates the difference in height between the tallest and shortest cow in the range.

Sample Input

6 3
1
7
3
4
2
5
1 5
4 6
2 2

Sample Output

6
3
0

Source

USACO 2007 January Silver

思路:区间最值问题。

详细分析见:POJ 3264 区间最值模板题


/*
*Accepted	
*8404 KB	
*3579 ms	
*G++	
*1022 B	2013-03-23 21:57:28
*O(n*logn) 
*第一次写RMQ套用lrj的模板,效率较低,模板较坑 Orz 
*/
#include<cstdio>
#include<cstring>
#include<cmath>
#include<algorithm>
using namespace std;

const int maxn = 50000+10;
int d_max[maxn][20];
int d_min[maxn][20];
int A[maxn];
int n,q;

void RMQ_init()
{
	for(int i = 1; i <= n; i++) d_max[i][0] = d_min[i][0] = A[i];
	for(int j = 1; j <= log((double)(n+1))/log(2.0); j++)
		for(int i = 1; i+(1<<j)-1 <= n; i++)
		{
			d_min[i][j] = min(d_min[i][j-1], d_min[i + (1<<(j-1))][j-1]);
			d_max[i][j] = max(d_max[i][j-1], d_max[i + (1<<(j-1))][j-1]);
		}	
}

int RMQ_Max(int L, int R)
{
	int k = (int)(log((double)(R-L+1)) / log(2.0));
	return max(d_max[L][k], d_max[R-(1 << k)+1][k]);
}
int RMQ_Min(int L, int R)
{
	int k = (int)(log((double)(R-L+1)) / log(2.0));
	return min(d_min[L][k], d_min[R-(1 << k)+1][k]);
}
int main()
{
	while(scanf("%d%d", &n, &q) != EOF)
	{
		for(int i = 1; i <= n; i++)
			scanf("%d", &A[i]);
		RMQ_init();
		
		int a,b;
		for(int i = 1; i <= q; i++)
		{
			scanf("%d%d", &a, &b);
			printf("%d\n",RMQ_Max(a,b) - RMQ_Min(a,b));
		}
	}
	return 0;
}
 


E

小明系列故事——师兄帮帮忙

Time Limit: 3000/1000 MS (Java/Others)    Memory Limit: 65535/32768 K (Java/Others)
Total Submission(s): 2043    Accepted Submission(s): 476


Problem Description
  小明自从告别了ACM/ICPC之后,就开始潜心研究数学问题了,一则可以为接下来的考研做准备,再者可以借此机会帮助一些同学,尤其是漂亮的师妹。这不,班里唯一的女生又拿一道数学题来请教小明,小明当然很高兴的就接受了。不过等他仔细读题以后,发现自己也不会做,这下小明囧了:如果回复说自己不懂,岂不是很没面子?
  所以,他现在私下求你帮忙解决这道题目,题目是这样的:
  给你n个数字,分别是a1,a2,a3,a4,a5……an,这些数字每过一个单位时间就会改变,假设上一个单位时间的数字为a1’,a2’,a3’……an’,那么这个单位时间的数字a[i] = a[i - 1]’ * K(i == 1的时候a[1] = a[n]’ * K),其中K为给定的系数。
  现在的问题就是求第t单位时间的时候这n个数字变成了什么了?由于数字可能会很大,所以只要你输出数字对10^9 + 7取余以后的结果。
 

Input
  输入数据第一行是一个正整数T,表示有T组测试数据;
  每组数据有两行,第一行包含输入三个整数n, t, k,其中n代表数字个数,t代表第t个单位时间,k代表系数;第二行输入n个数字ai,代表每个数字开始的时候是多少。

   [Technical Specification]
  T <= 100
  1 <= n <= 10 ^ 4
  0 <= t <= 10 ^ 9  其中 t = 0 表示初始状态
  1 <= k <= 10 ^ 9
  1 <= ai<= 10 ^ 9
 

Output
  对于每组数据请输出第t单位时间后这n个数字变成了什么,输出的时候 每两个数字之间输出一个空格,行末不要输出多余的空格,具体见样例。
 

Sample Input
   
   
   
   
2 3 2 5 1 2 3 3 0 5 1 2 3
 

Sample Output
   
   
   
   
50 75 25 1 2 3
 

Source
2013腾讯编程马拉松初赛第一场(3月21日)
 

Recommend
liuyiding

思路:幂取模问题。

            先将数组元素乘以 k^t %mod ,然后再对应于数组元素个数 n 确定其周期性,根据 t%n 顺时针旋转来确定首位置。

  (PS:测试时注意首位置不要比 n 大)。


注意:整数的溢出(int *int 可能会超int)

             循环输出时,首位置的确定,最好用下面那组数据测试一下,否则WA到正无穷啊大哭

#include<cstdio>
const int maxn = 10000+10;
const int mod = 1000000000+7;

int a[maxn];
int n,t,k;

int mul(int m,int n)//m^n
{
	int b = 1;
	while(n>0)
	{
		if(n&1) b = ((long long)b*m)%mod;
		n = n >>1;
		m = ((long long)m*m)%mod;
	}
	return (int)b;
	
}

int main()
{
	int T;
	scanf("%d", &T);
	while(T--)
	{
		scanf("%d%d%d", &n, &t, &k);
		for(int i = 1; i <= n; i++)
			scanf("%d",&a[i]);
		 
		int temp = mul(k,t);
		for(int i = 1; i <= n; i++)
		{
			a[i] = ((long long)a[i]*temp)%mod;
			a[i] = (int)a[i];
		}
			
		t%=n; 
	 
		int x =(n-t+1) ;
		if(x>n) x%=n;//printf("%d\n",x);
  		for(int i = x; i <= n; i++)
    	{
    		if(i == x) printf("%d",a[i]);
     		else printf(" %d",a[i]);
        }
		for(int i=1; i < x; i++)
			printf(" %d",a[i]);
			
		printf("\n");
//printf("\n");//
	}
	return 0;
}
/*
6
4 1 1 
1 2 3 4
4 2 1
1 2 3 4
4 3 1
1 2 3 4
4 4 1
1 2 3 4
4 5 1
1 2 3 4
4 6 1
1 2 3 4
*/


F

哈密顿绕行世界问题

Time Limit: 3000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 612    Accepted Submission(s): 369


Problem Description
一个规则的实心十二面体,它的 20个顶点标出世界著名的20个城市,你从一个城市出发经过每个城市刚好一次后回到出发的城市。 
 

Input
前20行的第i行有3个数,表示与第i个城市相邻的3个城市.第20行以后每行有1个数m,m<=20,m>=1.m=0退出.
 

Output
输出从第m个城市出发经过每个城市1次又回到m的所有路线,如有多条路线,按字典序输出,每行1条路线.每行首先输出是第几条路线.然后个一个: 后列出经过的城市.参看Sample output
 

Sample Input
   
   
   
   
2 5 20 1 3 12 2 4 10 3 5 8 1 4 6 5 7 19 6 8 17 4 7 9 8 10 16 3 9 11 10 12 15 2 11 13 12 14 20 13 15 18 11 14 16 9 15 17 7 16 18 14 17 19 6 18 20 1 13 19 5 0
 

Sample Output
   
   
   
   
1: 5 1 2 3 4 8 7 17 18 14 15 16 9 10 11 12 13 20 19 6 5 2: 5 1 2 3 4 8 9 10 11 12 13 20 19 18 14 15 16 17 7 6 5 3: 5 1 2 3 10 9 16 17 18 14 15 11 12 13 20 19 6 7 8 4 5 4: 5 1 2 3 10 11 12 13 20 19 6 7 17 18 14 15 16 9 8 4 5 5: 5 1 2 12 11 10 3 4 8 9 16 15 14 13 20 19 18 17 7 6 5 6: 5 1 2 12 11 15 14 13 20 19 18 17 16 9 10 3 4 8 7 6 5 7: 5 1 2 12 11 15 16 9 10 3 4 8 7 17 18 14 13 20 19 6 5 8: 5 1 2 12 11 15 16 17 18 14 13 20 19 6 7 8 9 10 3 4 5 9: 5 1 2 12 13 20 19 6 7 8 9 16 17 18 14 15 11 10 3 4 5 10: 5 1 2 12 13 20 19 18 14 15 11 10 3 4 8 9 16 17 7 6 5 11: 5 1 20 13 12 2 3 4 8 7 17 16 9 10 11 15 14 18 19 6 5 12: 5 1 20 13 12 2 3 10 11 15 14 18 19 6 7 17 16 9 8 4 5 13: 5 1 20 13 14 15 11 12 2 3 10 9 16 17 18 19 6 7 8 4 5 14: 5 1 20 13 14 15 16 9 10 11 12 2 3 4 8 7 17 18 19 6 5 15: 5 1 20 13 14 15 16 17 18 19 6 7 8 9 10 11 12 2 3 4 5 16: 5 1 20 13 14 18 19 6 7 17 16 15 11 12 2 3 10 9 8 4 5 17: 5 1 20 19 6 7 8 9 10 11 15 16 17 18 14 13 12 2 3 4 5 18: 5 1 20 19 6 7 17 18 14 13 12 2 3 10 11 15 16 9 8 4 5 19: 5 1 20 19 18 14 13 12 2 3 4 8 9 10 11 15 16 17 7 6 5 20: 5 1 20 19 18 17 16 9 10 11 15 14 13 12 2 3 4 8 7 6 5 21: 5 4 3 2 1 20 13 12 11 10 9 8 7 17 16 15 14 18 19 6 5 22: 5 4 3 2 1 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 23: 5 4 3 2 12 11 10 9 8 7 6 19 18 17 16 15 14 13 20 1 5 24: 5 4 3 2 12 13 14 18 17 16 15 11 10 9 8 7 6 19 20 1 5 25: 5 4 3 10 9 8 7 6 19 20 13 14 18 17 16 15 11 12 2 1 5 26: 5 4 3 10 9 8 7 17 16 15 11 12 2 1 20 13 14 18 19 6 5 27: 5 4 3 10 11 12 2 1 20 13 14 15 16 9 8 7 17 18 19 6 5 28: 5 4 3 10 11 15 14 13 12 2 1 20 19 18 17 16 9 8 7 6 5 29: 5 4 3 10 11 15 14 18 17 16 9 8 7 6 19 20 13 12 2 1 5 30: 5 4 3 10 11 15 16 9 8 7 17 18 14 13 12 2 1 20 19 6 5 31: 5 4 8 7 6 19 18 17 16 9 10 3 2 12 11 15 14 13 20 1 5 32: 5 4 8 7 6 19 20 13 12 11 15 14 18 17 16 9 10 3 2 1 5 33: 5 4 8 7 17 16 9 10 3 2 1 20 13 12 11 15 14 18 19 6 5 34: 5 4 8 7 17 18 14 13 12 11 15 16 9 10 3 2 1 20 19 6 5 35: 5 4 8 9 10 3 2 1 20 19 18 14 13 12 11 15 16 17 7 6 5 36: 5 4 8 9 10 3 2 12 11 15 16 17 7 6 19 18 14 13 20 1 5 37: 5 4 8 9 16 15 11 10 3 2 12 13 14 18 17 7 6 19 20 1 5 38: 5 4 8 9 16 15 14 13 12 11 10 3 2 1 20 19 18 17 7 6 5 39: 5 4 8 9 16 15 14 18 17 7 6 19 20 13 12 11 10 3 2 1 5 40: 5 4 8 9 16 17 7 6 19 18 14 15 11 10 3 2 12 13 20 1 5 41: 5 6 7 8 4 3 2 12 13 14 15 11 10 9 16 17 18 19 20 1 5 42: 5 6 7 8 4 3 10 9 16 17 18 19 20 13 14 15 11 12 2 1 5 43: 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 1 2 3 4 5 44: 5 6 7 8 9 16 17 18 19 20 1 2 12 13 14 15 11 10 3 4 5 45: 5 6 7 17 16 9 8 4 3 10 11 15 14 18 19 20 13 12 2 1 5 46: 5 6 7 17 16 15 11 10 9 8 4 3 2 12 13 14 18 19 20 1 5 47: 5 6 7 17 16 15 11 12 13 14 18 19 20 1 2 3 10 9 8 4 5 48: 5 6 7 17 16 15 14 18 19 20 13 12 11 10 9 8 4 3 2 1 5 49: 5 6 7 17 18 19 20 1 2 3 10 11 12 13 14 15 16 9 8 4 5 50: 5 6 7 17 18 19 20 13 14 15 16 9 8 4 3 10 11 12 2 1 5 51: 5 6 19 18 14 13 20 1 2 12 11 15 16 17 7 8 9 10 3 4 5 52: 5 6 19 18 14 15 11 10 9 16 17 7 8 4 3 2 12 13 20 1 5 53: 5 6 19 18 14 15 11 12 13 20 1 2 3 10 9 16 17 7 8 4 5 54: 5 6 19 18 14 15 16 17 7 8 9 10 11 12 13 20 1 2 3 4 5 55: 5 6 19 18 17 7 8 4 3 2 12 11 10 9 16 15 14 13 20 1 5 56: 5 6 19 18 17 7 8 9 16 15 14 13 20 1 2 12 11 10 3 4 5 57: 5 6 19 20 1 2 3 10 9 16 15 11 12 13 14 18 17 7 8 4 5 58: 5 6 19 20 1 2 12 13 14 18 17 7 8 9 16 15 11 10 3 4 5 59: 5 6 19 20 13 12 11 10 9 16 15 14 18 17 7 8 4 3 2 1 5 60: 5 6 19 20 13 14 18 17 7 8 4 3 10 9 16 15 11 12 2 1 5
 

Author
Zhousc
 

Source
ECJTU 2008 Summer Contest
 

Recommend
lcy


思路:简单DFS应用,记录路径。注意格式和输出顺序要先给点排序,还有就是执行dfs的条件要注意下,我标记了的。


 
 
 
 
/*
*F	
*Accepted	
*204 KB	
*0 ms	
*G++	
*867 B	
*2013-03-26 
*/ 
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;

int path[22];
int point[21][3];
bool vis[21];

int m;
int Case;

void dfs(int a, int n)
{
	vis[a] = true;
	path[n] = a;
	if(n == 21 && path[n] == m) //回到起点 
	{
		printf("%d: ",++Case);
		for(int i = 1; i <= 21; i++) printf(" %d", path[i]);
		printf("\n");
		return;
	}
	else if(n >= 21) return;
	for(int i = 0; i < 3; i++)
	{
		int x = point[a][i];
		if((x != m && !vis[x]) || (x == m && n == 20)) //如果没有走过,或者下一个点回到起点 
		{ //注意:前一个条件如果没有写 x != m 则会影响后面的结果 也就是 m 会在路径中重复出现 
			dfs(x, n+1);
			vis[x] = false;
		} 
	} 
}
int main()
{
	for(int i = 1; i <= 20; i++)
	{
		scanf("%d%d%d", &point[i][0], &point[i][1], &point[i][2]);
		sort(point[i], point[i]+3);
	}
	 
	while(scanf("%d", &m) != EOF)
	{
		Case = 0;
		if(m == 0) break;
		
		memset(vis, false, sizeof(vis));
		
		dfs(m, 1);
	}
	return 0;
}


G

Coins
Time Limit: 1000MS   Memory Limit: 131072K
Total Submissions: 6465   Accepted: 4215

Description

Snoopy has three coins. One day he tossed them on a table then and tried to flip some of them so that they had either all heads or all tails facing up. After several attempts, he found that regardless of the initial configuration of the coins, he could always achieve the goal by doing exactly two flippings, under the condition that only one coin could be flipped each time and a coin could be flipped more than once. He also noticed that he could never succeed with less than two flippings.

Snoopy then wondered, if he had n coins, was there a minimum number x such that he could do exactly x flippings to satisfy his requirements?

Input

The input contains multiple test cases. Each test case consists of a single positive integer n (n < 10,000) on a separate line. A zero indicates the end of input and should not be processed.

Output

For each test case output a single line containing your answer without leading or trailing spaces. If the answer does not exist, output “No Solution!

Sample Input

2
3
0

Sample Output

No Solution!
2

Source

POJ Monthly--2007.04.01, Snoopy

比赛时实在没看懂是什么意思,现在想起,就算当时看懂了也应该不会想到这儿吧。。。下面copy个牛人的分析。


分析来自:点击打开链接


题意:Snoopy想问下,若有n枚硬币,这n枚硬币的初始状态是任意的,则至少需要翻转几次,才能保证对于任何一种初始状态而         言,都能变成n枚硬币全为正或全为反。

 

思路:若n为偶数:

      1: 若初始状态为偶数正面 + 偶数反面,要想变成全正或全反,翻转的次数必为偶数。

         例如: ○○●●●●  则翻转 2,4,6,8……次均可。

      2: 若初始状态为奇数正面 + 奇数反面,要想变成全正或全反,翻转的次数必为奇数。

         例如: ○○○○○●  则翻转 1,3(先将●翻为○,再将任一个○翻两下),5,7……次均可。

      因次,我们就无法得到一个确定的翻转次数x,让它能使任意初始状态的硬币变成全为正或全为反,因为若x为偶数,则无法满足例2,若x为奇数,则无法满足例1。故应输出"No Solution!"。

      若n为奇数:

      初始状态只可能为偶数正面 + 奇数反面(偶数反面 + 奇数正面同理),故要想变成全正或全反,是必能找出一个次数x满足所有任意情况的。

      1:对初始状态即全为奇数个正面而言,翻转的次数必为偶数。

      2: 由1得只能翻所有正面为反面,因为这样才需翻转偶数次。

         例如: ○○○○●●●  则翻转4,6,8,10……次均可,其中最小为4。要保证对7枚硬币的任意初始状态都可行,则最小应为 7-1=6 ,否则对 ○○○○○○● 无法实现。 

      因此,当你为奇数是,最少翻转次数为n-1。 

 

源代码:(这题考的是题意和推理,不是代码)


/*
*Accepted	
*132 KB	
*0 ms	
*C++	
*176 B	
*/
#include<cstdio>
int main()
{
	int n;
	while(scanf("%d", &n) != EOF)
	{
		if(n == 0) break;
		if(n%2 == 0) printf("No Solution!\n");
		else printf("%d\n", n-1);
	}
	return 0;
}


H

Quicksum
Time Limit: 1000MS   Memory Limit: 65536K
Total Submissions: 11832   Accepted: 8152

Description

A checksum is an algorithm that scans a packet of data and returns a single number. The idea is that if the packet is changed, the checksum will also change, so checksums are often used for detecting transmission errors, validating document contents, and in many other situations where it is necessary to detect undesirable changes in data.

For this problem, you will implement a checksum algorithm called Quicksum. A Quicksum packet allows only uppercase letters and spaces. It always begins and ends with an uppercase letter. Otherwise, spaces and letters can occur in any combination, including consecutive spaces.

A Quicksum is the sum of the products of each character's position in the packet times the character's value. A space has a value of zero, while letters have a value equal to their position in the alphabet. So, A=1, B=2, etc., through Z=26. Here are example Quicksum calculations for the packets "ACM" and "MID CENTRAL":

        ACM: 1*1  + 2*3 + 3*13 = 46

MID CENTRAL: 1*13 + 2*9 + 3*4 + 4*0 + 5*3 + 6*5 + 7*14 + 8*20 + 9*18 + 10*1 + 11*12 = 650

Input

The input consists of one or more packets followed by a line containing only # that signals the end of the input. Each packet is on a line by itself, does not begin or end with a space, and contains from 1 to 255 characters.

Output

For each packet, output its Quicksum on a separate line in the output.

Sample Input

ACM
MID CENTRAL
REGIONAL PROGRAMMING CONTEST
ACN
A C M
ABC
BBC
#

Sample Output

46
650
4690
49
75
14
15

Source

Mid-Central USA 2006

思路:字符串简单处理,直接看代码即可,注意空格的处理就好了。

#include<cstdio>
#include<cstring>

char s[300];
int main()
{
	char c;
	int ans = 0;;
	while((c=getchar()) != '#')
	{
		ans = 0;
		int k = 0;
		memset(s,-1,sizeof(s));
		if(c != '\n')
		{
			if(c != ' ') s[k++] = c -'A'+1;
			else s[k++] = 0;
		}
		
		while((c=getchar()) != '\n')
		{
			if(c != ' ') s[k++] = c -'A'+1;
			else s[k++] = 0;
		}
		for(int i = 0; i < k; i++)
		{//printf("%d ",s[k])
			ans += s[i]*(i+1);
		}
		printf("%d\n", ans);
		ans = 0;
		k = 0;
		memset(s,-1,sizeof(s));
	}
	return 0;
}



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