B

B - Smartphone Addiction 

简单模拟题，几个需要进行判断的点：

①. 到第一个咖啡馆时有没有电

②. 在咖啡馆充满电后就不能再充电了

③. 从咖啡馆回家后有没有电

#include <bits/stdc++.h>
using namespace std;

int a[1010], b[1010];
int main(){
    int n, m, t;
    cin >> n >> m >> t;
    for(int i = 1; i <= m; i ++)
        cin >> a[i] >> b[i];
    if(n - a[1] <= 0){
        cout << "No" << endl;
        return 0;
    }else{
        int sum1 = 0;
        sum1 = n - a[1];
        for(int i = 1; i <= m - 1; i ++){
            if(sum1 + b[i] - a[i] >= n)
                sum1 = n;
            else
                sum1 += b[i] - a[i];
                
            if(sum1 - a[i + 1] + b[i] <= 0){
                cout << "No" << endl;
                return 0;
            }else
                sum1 -= (a[i + 1] - b[i]);
        }
        if(sum1 + b[m] - a[m] >= n)
            sum1 = n;
        else
            sum1 += b[m] - a[m];
            
        if(sum1 - (t - b[m]) <= 0){
            cout << "No" << endl;
            return 0;
        }
        cout << "Yes" << endl;
    }
    
    
    return 0;
}