[알고리즘 ]백준 5612 - 터널의 입구와 출구 (C++)

[문제 링크] : https://www.acmicpc.net/problem/5612

#include <iostream>
using namespace std;

int main(){
    int N, M, A, B;
    cin >> N >> M;

    int Ans = M;
    for(int i=0; i<N; i++){
        cin >> A >> B;
        M += A - B;

        if(M < 0){
            Ans = 0;
            break;
        }

        if(M >= Ans){
            Ans = M;
        }
    }
    cout << Ans << "\n";
    return 0;
}