BOJ - 14719 - 빗물

import sys

def solution():
    H, W = map(int, sys.stdin.readline().split())
    block = list(map(int, sys.stdin.readline().split()))

    blockMap = [[0 for _ in range(501)] for _ in range(501)]
    for i in range(W):
        for j in range(block[i]):
            blockMap[j][i] = 1

    ret = 0
    for i in range(H):
        flag = False
        temp = 0
        for j in range(W):
            if flag:
                if blockMap[i][j] == 1:
                    ret += temp
                    temp = 0
                else:
                    temp += 1
            else:
                if blockMap[i][j] == 1:
                    flag = True

    print(ret)
solution()

https://www.acmicpc.net/problem/14719