boj 25556 포스택

Author: emost22

stack/25556.cpp

@@ -0,0 +1,60 @@
+#include <iostream>
+#include <algorithm>
+#include <stack>
+#define MAX 100001
+using namespace std;
+
+stack<int> s[4];
+int list[MAX];
+int N;
+
+void func() {
+	s[0].push(0);
+	s[1].push(0);
+	s[2].push(0);
+	s[3].push(0);
+	for (int i = 1; i <= N; i++) {
+		int minIdx = -1;
+		int minDiff = 1e9;
+		for (int j = 0; j < 4; j++) {
+			if (s[j].empty()) {
+				minIdx = j;
+				break;
+			}
+
+			if (s[j].top() > list[i]) continue;
+
+			int diff = abs(s[j].top() - list[i]);
+			if (diff < minDiff) {
+				minDiff = diff;
+				minIdx = j;
+			}
+		}
+
+		if (minIdx == -1) {
+			cout << "NO\n";
+			return;
+		}
+		
+		s[minIdx].push(list[i]);
+	}
+
+	cout << "YES\n";
+}
+
+void input() {
+	cin >> N;
+	for (int i = 1; i <= N; i++) {
+		cin >> list[i];
+	}
+}
+
+int main() {
+	cin.tie(NULL); cout.tie(NULL);
+	ios::sync_with_stdio(false);
+
+	input();
+	func();
+
+	return 0;
+}