T2691 桶哥的问题——送桶

这个题其实不难，就是按照结束时候的顺序从大到小走一遍，能送的就送，如果区间不重合就更新一下

代码：

#include<iostream>

#include<cstdio>

#include<cstdlib>

#include<algorithm>

#include<cstring>

#include<string>

#include<queue>

#include<stack>

#include<time.h>

using namespace std;

typedef long long ll;

ll read(){

    int ans=;

    char last=' ',ch=getchar();

    while(ch<'' || ch>'')last=ch,ch=getchar();

    while(ch>='' && ch<='')ans=ans*+ch-'',ch=getchar();

    if(last=='-')ans=-ans;

    return ans;

}

const int N=1e6+;

//ll a[N],b[N],c[N],n,m,ans;

//ll sum;

ll t,n;

struct qwq

{

    ll a,b;

}num[N];

bool cmp(qwq x,qwq y)

{

    return x.b>y.b;

}

int main()

{

    n=read();

    for(int i=;i<=n;i++)

    {

        num[i].a=read();

        num[i].b=read();

    }

    sort(num+,num++n,cmp);

    t=num[].b;

    for(int i=;i<=n;i++)

    {

        if(t>num[i].b)t=num[i].b;

        t-=num[i].a;

    }

    cout<<t;

}