''' mbinary
#########################################################################
# File : work_dispatch.py
# Author: mbinary
# Mail: zhuheqin1@gmail.com
# Blog: https://mbinary.xyz
# Github: https://github.com/mbinary
# Created Time: 2019-04-16  09:41
# Description:
#########################################################################
'''
'''
设有n件工作要分配给n个人去完成，将工作i分配给第j个人所需费用为c_ij 。试设计一个算法，为每个人分配1件不同的工作，并使总费用达到最小。
'''




import random
def dispatch(mat):
    '''mat: matrix of c_ij'''
    def _util(i, arrange, cost):
        ''' for i-th  work'''
        nonlocal total, used, rst
        if i == n:
            total = cost
            rst = arrange.copy()  # copy is needed
        else:
            for j in range(n):
                if not used[j] and(total is None or cost+mat[i][j] < total):
                    used[j] = True
                    arrange[i] = j
                    _util(i+1, arrange, cost+mat[i][j])
                    used[j] = False
    total = None
    rst = None
    n = len(mat)
    used = [False for i in range(n)]
    _util(0, [-1]*n, 0)
    return total, rst


if __name__ == '__main__':
    n = 10
    mat = [[random.randint(1, 100) for i in range(n)] for i in range(n)]
    print('work matrix: c_ij: work_i and person_j')
    for i in range(n):
        print(mat[i])
    print('result: ', end='')
    print(dispatch(mat))
