POJ 3258 River Hopscotch 二分枚举

题目：http://poj.org/problem?id=3258

又A一道，睡觉去了。。

#include <stdio.h>
#include <algorithm>

int d[50010];
int s, n, m;

bool judge(int mid)
{
    int sum = 0, cnt = 0;
    for(int i = 1; i <= n+1; i++)
    {
        sum += d[i] - d[i-1];
        if(sum < mid)
            cnt++;
        else
            sum = 0;
    }
    if(cnt > m)
        return 1;
    else return 0;
}

int main()
{
    scanf("%d %d %d", &s, &n, &m);
    for(int i = 1; i <= n; i++)
    {
        scanf("%d", &d[i]);
    }
    d[0] = 0;
    d[n+1] = s;
    std::sort(d, d+n+2);

    int low = 0, high = s+1, mid;
    while(low < high)
    {
        mid = (high + low) / 2;
        if(judge(mid))
            high = mid;
        else
            low = mid + 1;
    }
    printf("%d\n", low-1);
    return 0;
}