'commit'

TangDou/AcWing_TiGao/T5/QMI/1289_2.cpp

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+#include <bits/stdc++.h>
+using namespace std;
+#define int long long
+
+const int MOD = 200907;
+
+// 龟速乘，快速加
+int qadd(int a, int b) {
+    int res = 0;
+    while (b) {
+        if (b & 1) res = (res + a) % MOD;
+        b >>= 1;
+        a = (a + a) % MOD;
+    }
+    return res;
+}
+
+// 快速幂
+int qmi(int a, int b) {
+    int res = 1;
+    while (b) {
+        if (b & 1) res = (res * a) % MOD;
+        b >>= 1;
+        a = a * a % MOD;
+    }
+    return res;
+}
+
+signed main() {
+    int T;
+    cin >> T;
+    while (T--) {
+        int a, b, c, k;
+        cin >> a >> b >> c >> k;
+        if (a + c == b + b)
+            cout << (qadd(b - a, k - 1) + a) % MOD << endl; // 为等差即套公式，首项+公差*（项数-1）
+        else
+            cout << qmi(b / a, k - 1) * a % MOD << endl; // 等比数列用快速幂算末项
+    }
+}