Codeforces Round #350 (Div. 2) D2. Magic Powder

题目链接：

http://codeforces.com/contest/670/problem/D2

题解：

二分答案。

#include<iostream>
#include<cstdio>
#include<cstring>
#include<map>
using namespace std;

const int maxn = 100000 + 10;
const int INF = 2e9;
typedef __int64 LL;

int n, k;
int x[maxn], y[maxn];

bool solve(int num, LL kk) {
    for (int i = 0; i < n; i++) {
        if ((LL)x[i] * num>y[i]) {
            kk -= ((LL)x[i] * num - y[i]);
        }
        if (kk < 0) return false;
    }
    return true;
}

int main() {
    scanf("%d%d", &n, &k);
    for (int i = 0; i < n; i++) scanf("%d", x + i);
    for (int i = 0; i < n; i++) scanf("%d", y + i);
    int l = 0, r = INF + 1;
    while (l < r - 1) {
        int mid = l + (r - l) / 2;
        if (solve(mid, k)) l = mid;
        else r = mid;
    }
    printf("%d
", l);
    return 0;
}