AcWing 830. 单调栈

Posted 2020-12-19 wisexu

AcWing 830. 单调栈

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#include <bits/stdc++.h>
using namespace std;
const int N=1e6+10;
int n;
int stk[N],tt;
int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    cin>>n;
    for(int i=0;i<n;i++){
        int x;
        cin>>x;
        while(tt&&stk[tt]>=x) tt--;
        if(tt) cout<<stk[tt]<<‘ ‘;
        else cout<<-1<<‘ ‘;
        stk[++tt]=x;
    }
    return 0;
}