Submission #1408138

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Source Code Expand

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

#define MAX 100002
int n;

vector<int> v;

vector<int> ar;
vector<int> cer;
bool ok(int val){
	ar.clear();
	for (int i = 0; i < v.size(); i++){
		ar.push_back(v[i] >= val);
	}
	cer.assign(ar.size(), 0);
	for (int i = 0; i < ar.size(); i++){
		if (ar[i]){
			if (i&&ar[i - 1]){
				cer[i] = ar[i];
			}
			if (i + 1 < ar.size() && ar[i + 1]){
				cer[i] = ar[i];
			}
		}
	}
	int u = n-1;
	if (cer[u]){
		return true;
	}
	int lef = 0;
	for (int i = 0; i < u; i++){
		if (cer[i]){
			lef = i + 1;
		}
	}
	int rig = ar.size() - 1;
	for (int i = ar.size() - 1; i > u; i--){
		if (cer[i]){
			rig = i-1;
		}
	}
	{
		int cnt = 0;
		int ich = rig;
		while (ar[ich]&&ich>=0){
			cnt++;
			ich -= 2;
		}
		if (ich < lef){
			return true;
		}
		int len = rig - ich+1;
		len /= 2;
		if (rig - lef + 1 <= u){
			return true;
		}
	}
	{
		int cnt = 0;
		int ich = lef;
		while (ar[ich] && ich < ar.size()){
			cnt++;
			ich += 2;
		}
		int len = ich - lef - 1;
		len /= 2;
		if (lef + len-1 >= u){
			return true;
		}
	}
	return false;
}

int main(){
	cin >> n;
	for (int i = 0; i < 2 * n - 1; i++){
		int a;
		scanf("%d", &a);
		v.push_back(a);
	}
	int u = n-1;
	int mint = max(min(v[u], v[u - 1]), min(v[u], v[u + 1]));
	int maxt = *max_element(v.begin(), v.end());
	while (mint + 1 < maxt){
		int mid = (mint + maxt) >> 1;
		if (ok(mid)){
			mint = mid;
		}
		else{
			maxt = mid - 1;
		}
	}
	if (ok(maxt)){
		cout << maxt << endl;
	}
	else{
		cout << mint << endl;
	}
	return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:79:18: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &a);
                  ^

Judge Result