[LUOGU] P2920 [USACO08NOV]时间管理Time Management

见7.3测试

#include<iostream>
#include<algorithm>
#include<cstdio>

using namespace std; 

const int MAXN=;

inline int rd(){
    int ret=,f=;char c;
    while(c=getchar(),!isdigit(c))f=c=='-'?-:;
    while(isdigit(c))ret=ret*+c-'',c=getchar();
    return ret*f;
}

struct Node{
    int lon,tim;
}nodes[MAXN];
bool cmp(const Node &x,const Node &y){
    return x.tim<y.tim;
}

int n;

int main(){
//    freopen("manage.in","r",stdin);
//    freopen("manage.out","w",stdout);
    n=rd();
    for(int i=;i<=n;i++){
        nodes[i].lon = rd();
        nodes[i].tim = rd();
    }
    sort(nodes+,nodes++n,cmp);
    long long sum=,mn=(<<),v;
    for(int i=;i<=n;i++){
        sum+=nodes[i].lon;
        v=nodes[i].tim-sum;
        if(v<) return puts("-1"),;
        mn=min(mn,v);
    }
    printf("%lld",mn);
    return ;
}