题目：https://www.acwing.com/problem/content/description/4171/
通过率：11/13
代码：

#include<iostream>
#include<string>
#include<cmath>
#include<stdio.h>
using namespace std;
int main(){
    int a,b;
    int n=0,d=0,dd=0;
    cin>>a>>b;
    int p[30001],q[30001],x[30001],y[30001]={0};
    for(int i=1;i<=b;i++){
        cin>>p[i]>>q[i]>>x[i];
    }
    int zuixiao = 30000,i;
    for(int bbb = 1;bbb<=b;bbb++){
        zuixiao = 30000;
        for(int dp = 1;dp<=b;dp++){
            if(q[dp] < zuixiao){
                i = dp;
                zuixiao = q[dp];
            }
        }
        //cout<<i<<endl;
        for(int j=p[i];j<=q[i];j++){
            if(y[j] == 1){
                x[i]-=1;
            }
        }
        if(x[i] > 0){
            d = 0,dd = 0;
            while(x[i]>0){
                if(y[q[i]-d] == 0){
                    y[q[i]-d] +=1;
                    n+=1;
                    x[i] -= 1;
                    dd+=1;
                    //cout<<q[i]-d<<endl;
                }
                d+=1;
            }

        }
        q[i] = 30001;
    }
    cout<<n;

}