http://codeforces.com/problemset/problem/4/B Before an Exam

大可以直接先加最小值然后去逐渐逼近目标值。

#include <iostream>
#include <queue>
#include <cstdio>
using namespace std;
int main()
{
    int d,sumTime,l[35],r[35],a[35];
    cin >> d >> sumTime;
    for(int i = 0;i < d;++i){
        cin >> l[i] >> r[i];
        a[i] = l[i];
    }
    int s = 0,f;
    for(int i = 0;i < d;++i){
        s += l[i];
    }
    if(s > sumTime){
        cout << "NO" << endl;
        return 0;
    }
    if(s == sumTime){
        puts("YES");
        for(int i = 0;i < d - 1;++i){
            printf("%d ",a[i]);
        }
        printf("%d\n",a[d - 1]);
        return 0;
    }
    f = sumTime - s;
    s = 0;
    for(int i = 0;i < d;++i){
        s += r[i];
    }
    if(s < sumTime){
        cout << "NO" << endl;
        return 0;
    }
    for(int i = 0;i < d;++i){
        if(r[i] - l[i] >= f){
            a[i] = l[i] + f;
            break;
        }
        a[i] = r[i];
        f = f - r[i] + l[i];
    }
    puts("YES");
    for(int i = 0;i < d - 1;++i){
            printf("%d ",a[i]);
        }
    printf("%d\n",a[d - 1]);
    return 0;
}