POJ 4135 月度开销

题目链接：http://bailian.openjudge.cn/practice/4135

 

 题目解析：二分选择答案

#include <bits/stdc++.h>
using namespace std;
int n, m;
const int N = 100010;
int a[N];
bool valid(int mid) {
    int group = 1, rest = mid;
    for (int i = 1; i <= n; i++) {
        if (rest >= a[i]) {
            rest -= a[i];
        } else {
            group++;
            rest = mid - a[i];
        }
    }
    return group <= m;
}
int main() {
    cin >> n >> m;
    int sum_of_ai = 0;
    int maxx = 0;
    for (int i = 1; i <= n; i++) {
        cin >> a[i];
        sum_of_ai += a[i];
        maxx = max(maxx, a[i]);
    }
    int l = maxx, r = sum_of_ai;
    while (l < r) {
        int mid = (l + r) >> 1;
        if (valid(mid)) {
            r = mid;
        } else {
            l = mid + 1;
        }
    }
    cout << l << endl;
    return 0;
}