Python——【USACO 3.3.5】——A Game

A Game
IOI'96 - Day 1

Consider the following two-player game played with a sequence of N positive integers (2 <= N <= 100) laid onto a 1 x N game board. Player 1 starts the game. The players move alternately by selecting a number from either the left or the right end of the gameboard. That number is then deleted from the board, and its value is added to the score of the player who selected it. A player wins if his sum is greater than his opponents.

Write a program that implements the optimal strategy. The optimal strategy yields maximum points when playing against the "best possible" opponent. Your program must further implement an optimal strategy for player 2.

PROGRAM NAME: game1

INPUT FORMAT

Line 1:N, the size of the boardLine 2-etc:N integers in the range (1..200) that are the contents of the game board, from left to right

SAMPLE INPUT (file game1.in)

64 7 2 95 2

OUTPUT FORMAT

Two space-separated integers on a line: the score of Player 1 followed by the score of Player 2.

SAMPLE OUTPUT (file game1.out)

18 11

N个正整数的序列，由玩家1开始，两人轮流从序列的任意一端取一个数，取数后该数字被去掉并累加到本玩家的得分中，当数取尽时，游戏结束。以最终得分多者为胜。编一个执行最优策略的程序，最优策略就是使玩家在与最好的对手对弈时，能得到的在当前情况下最大的可能的总分的策略。程序要始终为第二位玩家执行最优策略。

"""ID : mcdonne1LANG : PYTHONTASK : game1"""fin = open ('game1.in', 'r')fout = open ('game1.out', 'w')num = [0 for i in range (110)]tot = [0 for i in range (110)]f = [[0 for i in range (110)] for j in range (110)]r = fin.readline()n = int(r)cnt = 0while cnt < n :r = fin.readline().split()for i in range (len(r)) :cnt += 1num[cnt] = int(r[i])f[cnt][cnt] = num[cnt]tot[cnt] = tot[cnt - 1] + num[cnt]for i in range (n)[::-1]:for j in range (i + 1, n + 1) :f[i][j] = max (tot[j] - tot[i] - f[i + 1][j] + num[i], tot[j - 1] - tot[i - 1] - f[i][j - 1] + num[j])fout.write (str(f[1][n]) + ' ' + str(tot[n] - f[1][n]) + '\n')fin.close()fout.close()