题目链接

Monthly Expense POJ - 3273

思路

$$ 二分 $$

时间复杂度

$$ O(Nlog(\sum_{i = 1}^Na_i)) $$

代码

#include <cstdio>
#include <algorithm>

using namespace std;

const int MAXN = 1e5 + 10;

int n, m;
int a[MAXN];

bool check(int mid) {
    int cnt = 0;
    int cur = mid;
    for (int i = 1; i <= n; i++) {
        if (cur + a[i] > mid) {
            cur = a[i];
            cnt++;
            if (a[i] > mid) {
                return false;
            }
        } else {
            cur += a[i];
        }
    }
    return cnt <= m;
}

int main() {

    scanf("%d%d", &n, &m);// don't forget &
    for (int i = 1; i <= n; i++) {
        scanf("%d", &a[i]);// don't forget &
    }
    int l = 1, r = 1e9 + 10, ans = r;
    while (l <= r) {
        int mid = (l + r) >> 1;
        if (check(mid)) {
            ans = mid;
            r = mid - 1;
        } else {
            l = mid + 1;
        }
    }
    printf("%d", ans);
    return 0;
}