Initial commit: C++ courseware

2.Course/2.深入浅出程序设计竞赛（提高篇）/最短路/C++源码/07_10_p1037.cpp

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+// P1037 产生数。十个数字的自反传递闭包 + 十进制高精度乘法。
+#include <bits/stdc++.h>
+using namespace std;
+string mulSmall(string s, int k) {
+    int carry = 0;
+    for (int i = (int)s.size()-1; i >= 0; --i) {
+        int t = (s[i]-'0')*k + carry;
+        s[i] = char('0'+t%10); carry = t/10;
+    }
+    while (carry) { s.insert(s.begin(), char('0'+carry%10)); carry /= 10; }
+    return s;
+}
+int main() {
+    ios::sync_with_stdio(false); cin.tie(nullptr);
+    string number; int k; if (!(cin >> number >> k)) return 0;
+    bool reach[10][10] = {};
+    for (int i = 0; i < 10; ++i) reach[i][i] = true;
+    for (int i = 0, a, b; i < k; ++i) { cin >> a >> b; reach[a][b] = true; }
+    for (int mid = 0; mid < 10; ++mid)
+        for (int i = 0; i < 10; ++i)
+            for (int j = 0; j < 10; ++j)
+                reach[i][j] |= reach[i][mid] && reach[mid][j];
+    int choices[10] = {};
+    for (int a = 0; a < 10; ++a) for (int b = 0; b < 10; ++b) choices[a] += reach[a][b];
+    string ans = "1";
+    for (char digit : number) ans = mulSmall(ans, choices[digit-'0']);
+    cout << ans << '\n';
+}