【DP】 HDOJ 1422 重温世界杯

简单DP。。。

#include <iostream>  
#include <queue>  
#include <stack>  
#include <map>  
#include <set>  
#include <bitset>  
#include <cstdio>  
#include <algorithm>  
#include <cstring>  
#include <climits>  
#include <cstdlib>
#include <cmath>
#include <time.h>
#define maxn 200005
#define maxm 400005
#define eps 1e-10
#define mod 1000000007
#define INF 999999999
#define lowbit(x) (x&(-x))
#define mp mark_pair
#define ls o<<1
#define rs o<<1 | 1
#define lson o<<1, L, mid  
#define rson o<<1 | 1, mid+1, R  
//typedef vector<int>::iterator IT;
typedef long long LL;
//typedef int LL;
using namespace std;
LL qpow(LL a, LL b){LL res=1,base=a;while(b){if(b%2)res=res*base;base=base*base;b/=2;}return res;}
LL powmod(LL a, LL b){LL res=1,base=a;while(b){if(b%2)res=res*base%mod;base=base*base%mod;b/=2;}return res;}
void scanf(int &__x){__x=0;char __ch=getchar();while(__ch==' '||__ch=='\n')__ch=getchar();while(__ch>='0'&&__ch<='9')__x=__x*10+__ch-'0',__ch = getchar();}
LL gcd(LL _a, LL _b){if(!_b) return _a;else return gcd(_b, _a%_b);}
// head

int num[maxn], n, dp[maxn], mx, sum;

void read(void)
{
	int a, b;
	for(int i = 1; i <= n; i++) {
		scanf(a), scanf(b);//scanf("%d%d", &a, &b);
		num[i] = a - b;
	}
	int t = n<<1;
	for(int i = n+1; i <= t; i++) num[i] = num[i - n];
}
void work(void)
{
	mx = sum = 0;
	int t = n<<1;
	for(int i = 1; i <= t; i++) {
		sum += num[i];
		if(sum >= 0) dp[i] = dp[i-1] + 1;
		else {
			if(num[i] >= 0) dp[i] = 1;
			else dp[i] = 0;
			sum = 0;
		}
		mx = max(mx, dp[i]);
	}
	if(mx > n) mx = n;
	printf("%d\n", mx);
}
int main(void)
{
	while(scanf("%d", &n)!=EOF) {
		read();
		work();
	}
	return 0;
}