poj 3258 River Hopscotch

最小值的最大化问题！！！二分搞定……

代码如下：

 

 1 #include<iostream>

 2 #include<stdio.h>

 3 #include<algorithm>

 4 #include<iomanip>

 5 #include<cmath>

 6 #include<cstring>

 7 #include<vector>

 8 #define ll __int64

 9 #define pi acos(-1.0)

10 #define MAX 50000

11 using namespace std;

12 int an[100005];

13 int main(){

14     int n,m,i,sum,left,right=0,mid,t;

15     while(cin>>right>>n>>m){

16         an[0] = 0;

17         an[n+1] = right;

18         for (i=1;i<=n;i++)

19             cin>>an[i];

20         sort(an,an+n+1);

21         left = 0;

22         for (i=0;i<=n;i++){

23             an[i] = an[i+1]-an[i];

24             if (left > an[i]) left = an[i];

25         }

26         while (left<=right){

27             mid = (left+right)/2;

28             sum = 0;t = 0;

29             for (i=0;i<n;i++){

30                 if (sum+an[i]<mid){

31                     sum += an[i];

32                     t++;

33                 }

34                 else {

35                     sum = 0;

36                 }

37             }

38             if (t>m){//t>m,说明m取大了

39                 right = mid-1;

40             }

41             else{

42                 left = mid+1;

43             }

44         }

45         cout<<right<<endl;

46     }

47     return 0;

48 }

View Code