#910. [2018.8长郡集训day1]都市

https://sjzezoj.com/submission/59281

S2OJ/910/910.cpp

@@ -0,0 +1,79 @@
+#include <iostream>
+#include <algorithm>
+#include <unordered_map>
+#include <vector>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    int n;
+    std::vector<int> a;
+    std::vector<std::vector<int>> ans;
+
+    cin >> n;
+
+    for (int i = 1, x; i <= n * (n - 1) / 2; i++) {
+        cin >> x;
+
+        a.emplace_back(x);
+    }
+
+    std::sort(a.begin(), a.end());
+
+    for (int i = a[0] >> 1; i; i--) {
+        int b = a[0] - i,
+            c = a[1] - i;
+
+        if (*std::lower_bound(a.begin(), a.end(), b + c) != b + c) continue;
+
+        std::vector<int> v;
+        std::unordered_map<int, int> map;
+
+        for (int x : a) map[x]++;
+
+        v.emplace_back(i);
+        map[i + b]--;
+        v.emplace_back(b);
+        map[i + c]--;
+        v.emplace_back(c);
+        map[b + c]--;
+
+        bool flag = false;
+        for (int j = 2; j < a.size() && !flag; j++) {
+            if (!map[a[j]]) continue;
+
+            for (int x : v) {
+                if (!map.count(x + a[j] - i) || !map[x + a[j] - i]) {
+                    flag = true;
+
+                    break;
+                }
+
+                map[x + a[j] - i]--;
+            }
+
+            v.emplace_back(a[j] - i);
+        }
+
+        if (!flag) ans.emplace_back(v);
+    }
+
+    cout << ans.size() << endl;
+
+    std::sort(ans.begin(), ans.end(), std::greater<>());
+
+    for (auto item : ans) {
+        for (int x : item) {
+            cout << x << ' ';
+        }
+
+        cout << endl;
+    }
+
+    return 0;
+}