[HDU3555]Bomb
[HDU3555]Bomb
试题描述
The counter-terrorists found a time bomb in the dust. But this time the terrorists improve on the time bomb. The number sequence of the time bomb counts from 1 to N. If the current number sequence includes the sub-sequence "49", the power of the blast would add one point.
Now the counter-terrorist knows the number N. They want to know the final points of the power. Can you help them?
输入
The first line of input consists of an integer T (1 <= T <= 10000), indicating the number of test cases. For each test case, there will be an integer N (1 <= N <= 2^63-1) as the description.
The input terminates by end of file marker.
输出
For each test case, output an integer indicating the final points of the power.
输入示例
3 1 50 500
输出示例
0 1 15
数据规模及约定
见“输入”
题解
裸数位 dp,f[i][j] 表示前 i 位最高位为数字 j 的数中,包含“49”的个数。
#include <iostream> #include <cstdio> #include <algorithm> #include <cmath> #include <stack> #include <vector> #include <queue> #include <cstring> #include <string> #include <map> #include <set> using namespace std; #define LL long long LL read() { LL x = 0, f = 1; char c = getchar(); while(!isdigit(c)){ if(c == '-') f = -1; c = getchar(); } while(isdigit(c)){ x = x * 10 + c - '0'; c = getchar(); } return x * f; } #define maxn 21 LL f[maxn][maxn], ten[maxn]; int num[maxn], cnt; LL sum(LL x) { cnt = 0; LL orx = x; while(x) num[++cnt] = x % 10, x /= 10; LL sum = 0; for(int i = cnt; i; i--) { for(int j = 0; j < num[i]; j++) sum += f[i][j]; if(i < cnt && num[i+1] == 4 && num[i] == 9) { sum += orx % ten[i-1] + 1; break; } } return sum; } int main() { ten[0] = 1; for(int i = 1; i < maxn; i++) ten[i] = ten[i-1] * 10; for(int i = 1; i < maxn - 1; i++) for(int j = 0; j <= 9; j++) for(int k = 0; k <= 9; k++) { if(k == 4 && j == 9) f[i+1][k] += ten[i-1]; else f[i+1][k] += f[i][j]; } int T = read(); while(T--) { LL n = read(); printf("%lld\n", sum(n)); } return 0; }
打这种题最好写一发暴力。。。