Educational Codeforces Round 91 (Rated for Div. 2) A. Three Indices (模拟)

• 题意:有一长度为\(n\)的序列,问是否能找到\(a_{i}<a_{j},a_{j}>a_{k},(i<j<k)\),如果满足,输出其位置.

• 题解:直接暴力两头找即可,最坏复杂度:\(O(n^2)\).

• 代码:

  int t;
  int n;
  int a[N];
  
  int main() {
      ios::sync_with_stdio(false);cin.tie(0);
    	cin>>t;
    	 while(t--){
    	 	cin>>n;
    	 	 for(int i=1;i<=n;++i) cin>>a[i];
  
    	 	 bool ok=0;
    	 	 for(int j=1;j<=n;++j){
    	 	 	int pos1=-1;
    	 	 	int pos2=-1;
    	 	 	for(int i=1;i<j;++i){
    	 	 		if(a[i]<a[j]){
    	 	 			pos1=i;
    	 	 			break;
    	 	 		}
    	 	 	}
    	 	 	if(pos1==-1) continue;
    	 	 	for(int k=j+1;k<=n;++k){
    	 	 		if(a[k]<a[j]){
    	 	 			pos2=k;
    	 	 			break;
    	 	 		}
    	 	 	}
    	 	 	if(pos1!=pos2 && pos1!=-1 && pos2!=-1){
    	 	 		ok=1;
    	 	 		cout<<"YES"<<endl;
    	 	 		cout<<pos1<<" "<<j<<" "<<pos2<<endl;
    	 	 		break;
    	 	 	}
    	 	 }
    	 	 if(!ok) cout<<"NO"<<endl;
    	 }
  
      return 0;
  }