题解 | #非递减序列#

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

int main(){
    int m;
    stack<int> v;
    int c=0;
    while(cin>>m){
        if(v.empty()) v.push(m);
        else if(m<v.top()&&c==0) {//遇到第一个不满足条件的数
            v.pop();
            if(!v.empty()&&m<v.top()) { 
                cout<<0<<endl;return 0;
            }
            else if(v.empty()){
                v.push(m);
                v.push(m);
            }
            else {
                v.push(v.top());
                v.push(m);}
            c++;
        }else if(m<v.top()&&c){
            cout<<0<<endl;
            return 0;
        }else v.push(m);
    }
    cout<<1<<endl;
    return 0;
}