目录调整

00lanqiao chap/test99-4-2.cpp

@@ -0,0 +1,37 @@
+// 蓝桥 3008 特殊的三角形
+#include<bits/stdc++.h>
+using namespace std;
+const int N = 1e6+9;
+int cnt[N], prefix[N];
+
+void dfs(int dep, int st, int mul, int sum){
+    if(mul > 1e6) return;
+    if(dep == 4){
+        cnt[mul]++; 
+        return;
+    }
+    int up = pow(1e6 / mul, 1.0/(4-dep)) + 3;
+    for(int i = st + 1; i < (dep == 3?sum:up); i++){
+        dfs(dep+1, i, mul * i, sum + i);
+    }
+}
+
+int main(){
+    dfs(1, 0, 1, 0);
+    for(int i = 1; i <= 1e6; i++){
+        prefix[i] = prefix[i-1] + cnt[i];
+    }
+    int q; cin >> q;
+    while(q--){
+        int l, r; cin >> l >> r;
+        cout << prefix[r] - prefix[l-1] << '\n';
+    }
+    return 0;
+}
+/* test samples
+4 
+1 10
+30 50
+60 200
+200 400
+*/