题意:
#include <bits/stdc++.h> using namespace std; int main() { int n; int num[1007]; int kase = 0; while(scanf("%d", &n) != EOF && n != 0) { while(scanf("%d", &num[0]) && num[0] != 0){ stack<int> s1; num[1] = num[0]; for(int i = 2; i <= n; i++){ scanf("%d", num+i); } int ok = 0; int A = 1, B = 1; while(B <= n){ if(A == num[B]){A++; B++;} else if(!s1.empty() && s1.top() == num[B]){s1.pop(); B++;} else if(A <= n) s1.push(A++); else {ok =0; break;}; } if(ok) printf("Yes\n"); else printf("No\n"); } printf("\n"); } }