Description
Input
Output
Sample Input
3 1 50 500
Sample Output
0 1 15
Hint
From 1 to 500, the numbers that include the sub-sequence "49" are "49","149","249","349","449","490","491","492","493","494","495","496","497","498","499", so the answer is 15.
求1到n中不含49的数的个数
dp[i][j][0]代表i位的数,最高位为j时,没有出现49的个数
dp[i][j][1]代表i位的数,最高位为j时,出现49的个数
#include <cstdio> #include <cstring> #include <algorithm> using namespace std ; #define LL __int64 LL dp[25][10][2] ; int digit[25] , cnt ; void init() { int i , j , k ; memset(dp,0,sizeof(dp)) ; for(j = 0 ; j < 10 ; j++) dp[1][j][0] = 1 ; for(i = 2 ; i <= 20 ; i++) { for(j = 0 ; j < 10 ; j++) { for(k = 0 ; k < 10 ; k++) { dp[i][j][1] += dp[i-1][k][1] ; if( j == 4 && k == 9 ) dp[i][j][1] += dp[i-1][k][0] ; else dp[i][j][0] += dp[i-1][k][0] ; } //printf("dp[%d][%d] %I64d %I64d\n", i , j , dp[i][j][0], dp[i][j][1]) ; } } return ; } LL solve(LL temp) { int flag , i , j ; LL ans = 0 ; memset(digit,0,sizeof(digit)) ; cnt = 0 ; while( temp ) { digit[++cnt] = temp % 10 ; temp /= 10 ; } for(j = 0 ; j < digit[cnt] ; j++) ans += dp[cnt][j][1] ; flag = 0 ; for(i = cnt-1 ; i > 0 ; i--) { for(j = 0 ; j < digit[i] ; j++) { ans += dp[i][j][1] ; if( flag ) ans += dp[i][j][0] ; } if( digit[i+1] == 4 && digit[i] == 9 ) flag = 1 ; } return ans ; } int main() { LL t , n , ans ; init() ; scanf("%I64d", &t) ; while( t-- ) { scanf("%I64d", &n) ; ans = solve(n+1) ; printf("%I64d\n", ans) ; } return 0; }