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基本的数位dp,需要记录前面除以13的余数。
#include <cstdio> #include <cstring> using namespace std; #define D(x) x const int MAX_DIGIT = 35; int n, m; int f[MAX_DIGIT]; int memoize[MAX_DIGIT][2][2][2][13]; void to_digits(int a) { for (int i = 0; i < MAX_DIGIT; i++) { f[i] = a % 10; a /= 10; } } int dfs(int digit, bool less, bool contain, bool one, int remain) { if (digit == -1) { return contain && !remain; } if (memoize[digit][less][contain][one][remain] != -1) { return memoize[digit][less][contain][one][remain]; } int limit = less ? 9 : f[digit]; int ret = 0; for (int i = 0; i <= limit; i++) { int new_remain = (remain * 10 + i) % 13; if (i == 3 && one) { ret += dfs(digit - 1, less || i < f[digit], true, false, new_remain); continue; } if (i == 1) { ret += dfs(digit - 1, less || i < f[digit], contain, true, new_remain); continue; } ret += dfs(digit - 1, less || i < f[digit], contain, false, new_remain); } memoize[digit][less][contain][one][remain] = ret; return ret; } int main() { while (scanf("%d", &n) != EOF) { to_digits(n); memset(memoize, -1, sizeof(memoize)); int ans = dfs(32, false, false, false, 0); printf("%d\n", ans); } return 0; }
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原文地址:http://www.cnblogs.com/rainydays/p/4281601.html