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1、
2、题目:
Problem A Pebble Solitaire Input: standard input
Output: standard output Time Limit: 1 secondPebble solitaire is an interesting game. This is a game where you are given a board with an arrangement of small cavities, initially all but one occupied by a pebble each. The aim of the game is to remove as many pebbles as possible from the board. Pebbles disappear from the board as a result of a move. A move is possible if there is a straight line of three adjacent cavities, let us call them A, B, and C, with B in the middle, where A is vacant, but B and C each contain a pebble. The move constitutes of moving the pebble from C to A, and removing the pebble in Bfrom the board. You may continue to make moves until no more moves are possible.
In this problem, we look at a simple variant of this game, namely a board with twelve cavities located along a line. In the beginning of each game, some of the cavities are occupied by pebbles. Your mission is to find a sequence of moves such that as few pebbles as possible are left on the board.
Input
The input begins with a positive integer n on a line of its own. Thereafter n different games follow. Each game consists of one line of input with exactly twelve characters, describing the twelve cavities of the board in order. Each character is either '-' or 'o' (The fifteenth character of English alphabet in lowercase). A '-' (minus) character denotes an empty cavity, whereas a 'o' character denotes a cavity with a pebble in it. As you will find in the sample that there may be inputs where no moves is possible.
For each of the n games in the input, output the minimum number of pebbles left on the board possible to obtain as a result of moves, on a row of its own.
5 ---oo------- -o--o-oo---- -o----ooo--- oooooooooooo oooooooooo-o | 1 2 3 12 1
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Swedish National Contest
类似于跳棋,当两颗石子左或者右有空位置时,移动。每次转移之后移去经过的石子。
思路:
有12个格子,所以状态最多有2^12=4096个。把每次搜索过的状态存在dp[]数组中,以后再次查询类似的直接返回即可。
3、AC代码:
#include#include #include #define min(a,b) (((a) < (b)) ? (a) : (b))int dp[4100];int solve(int n){ if (dp[n] != -1) return dp[n]; dp[n] = 0; for (int i = 0; i < 12; ++i) if (n & (1 << i)) dp[n] += 1; for (int i = 0; i < 10; ++i) { int t; if ((n&(1< << i); t &= ~(1 << (i+1)); t |= 1 << (i+2); dp[n] = min(dp[n], solve(t)); } if (!(n&(1< << (i+1)); t &= ~(1 << (i+2)); t |= 1 << i; dp[n] = min(dp[n], solve(t)); } } return dp[n];}int main(){ memset(dp, -1, sizeof(dp)); int cases; scanf("%d", &cases); while (cases--) { char str[20]; int n = 0; scanf("%s", str); for (int i = 0; i < 12; ++i) if (str[i] == 'o') n ^= 1 << i; printf("%d\n", solve(n)); } return 0;}
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