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Author: P1NGPING

24-game.cpp

@@ -0,0 +1,66 @@
+#include <iostream>
+using namespace std;
+
+int raw[4], pl[4], oper[3], cnt = 0; //oper:0 addition, 1 subtraction, 2 multiplication, 3 division
+bool visit[13];
+
+void dfs(int t);
+void operdfs(int t);
+void processoper();
+
+int main() {
+	for (int i = 0; i < 4; i++) cin >> raw[i];
+	dfs(0);
+	return 0;
+}
+
+void dfs(int t) {
+	if (t == 4) {
+		operdfs(0);
+		return;
+	}
+
+	for (int i = 0; i < 4; i++) {
+		if (!visit[raw[i]]) {
+			pl[t] = raw[i]; visit[raw[i]] = true;
+			dfs(t + 1);
+			visit[raw[i]] = false;
+		}
+	}
+}
+
+void operdfs(int t) { //t0=0
+	if (t == 3) {
+		processoper();
+		return;
+	}
+	for (int i = 0; i < 4; i++) {
+		oper[t] = i;
+		operdfs(t + 1);
+	}
+}
+
+void processoper() {
+	int res = pl[0];
+	for (int i = 0; i < 3; i++) {
+		switch (oper[i]) {
+		case 0: res += pl[i + 1]; break;
+		case 1: res -= pl[i + 1]; break;
+		case 2: res *= pl[i + 1]; break;
+		case 3: res /= pl[i + 1]; break;
+		}
+	}
+	if (res == 24) {
+		for (int i = 0; i < 3; i++) {
+			cout << pl[i] << " ";
+			switch (oper[i]) {
+			case 0: cout << "+ "; break;
+			case 1: cout << "- "; break;
+			case 2: cout << "* "; break;
+			case 3: cout << "/ "; break;
+			}
+		}
+		cout << pl[3] << endl;
+	}
+	return;
+}