'commit'

TangDou/KaoShi/小蓝突发奇想2.cpp

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+#include <bits/stdc++.h>
+
+using namespace std;
+int n, m;
+int cnt;
+vector<int> p1, p2;
+/**
+  测试数据：
+  5 1
+  答案：
+  3
+ */
+void dfs(int u) {
+    //收集答案
+    if (u == n + 1) {
+        int s1 = 0, s2 = 0;
+        for (int i = 0; i < p1.size(); i++)
+            s1 += p1[i];
+        for (int i = 0; i < p2.size(); i++)
+            s2 += p2[i];
+        if (s1 - s2 == m)
+            cnt++;
+        return;
+    }
+    p1.push_back(u);
+    dfs(u + 1);
+    p1.pop_back();
+
+    p2.push_back(u);
+    dfs(u + 1);
+    p2.pop_back();
+}
+int main() {
+    cin >> n >> m;
+    dfs(1);
+    cout << cnt << endl;
+    return 0;
+}