Tontti

import math

def treesInSq(sum, bX, bY, tX, tY):
    # a = tY
    # b = tX
    # c = bY
    # d = bX
    if tY == 0 and tX == 0:
        return sum[bY][bX]
    if tY == 0:
        return sum[bY][bX] - sum[bY][tX - 1]
    if tX == 0:
        return sum[bY][bX] - sum[tY - 1][bX]
    return sum[bY][bX] - sum[tY - 1][bX] - sum[bY][tX - 1] + sum[tY - 1][tX - 1]

# pisteestä x, y vasemmalle ylös alkavan neliön pienin mahdollinen sivun pituus, jolla neliössä on puita treeCount
def binarySearch(sumArr, treeCount, bX, bY):
    l = 0
    r = min(bX, bY)
    mid = 0
    
    while (l < r):
        mid = math.ceil((l + r) / 2)
        
        if (treesInSq(sumArr, bX, bY, bX - mid, bY - mid) > treeCount):
            r = mid - 1
        else:
            l = mid
            
    if l == r and treesInSq(sumArr, bX, bY, bX - mid, bY - mid):
        return bX - l
    return -1
    
def getLongestSide(sum, treeCount, bX, bY, minSideLength):
    for i in range(min(bX, bY) - minSideLength, -1, -1):
        if (treesInSq(sum, bX, bY, bX - i, bY - i) > treeCount):
            return min(bX, bY) - i
    return minSideLength    
        
    
    
# onko olemassa neliötä, alakulma (x, y), jonka alueella on tasan n puuta
def possibleSquaresFromPoint(sum, bX, bY, n):
    # minSideLength = binarySearch(sum, n, bX, bY)
    # if minSideLength == -1:
    #     return 0
    # maxSideLength = getLongestSide(sum, n, bX, bY, minSideLength)
    # return maxSideLength - minSideLength + 1
    possibilities = 0
    for i in range(0, min(bX, bY) + 1):
        treeCount = treesInSq(sum, bX, bY, bX - i, bY - i)
        
        if (treeCount == n):
            possibilities += 1 
        if (treeCount > n):
            break
    
    return possibilities    
    
# . tyhjä, * puu
height, width, trees = [int(x) for x in input().split(" ")]
# forest = []
treeSum = []

for j in range(0, height):
    forestRow = input()
    treeSum.append([])
    rivi = 0
    for i in range(0, width):
        if forestRow[i] == '*':
            rivi += 1
        treeSum[j].append(rivi)
        if j > 0:
            treeSum[j][i] += treeSum[j - 1][i]

# # summataulukko puiden määrästä vasemmasta yläkulmasta lähtien
# treeSum = [[0 for x in range(width)] for x in range(height)]
# 
# for j in range(0, height):
#     rivi = 0
#     for i in range(0, width):
#         if forest[j][i] == '*':
#             rivi += 1
#         treeSum[j][i] = rivi
#         if j > 0:
#             treeSum[j][i] += treeSum[j - 1][i]
            
ways = 0

for j in range(0, height):
    for i in range(0, width):
        ways += possibleSquaresFromPoint(treeSum, i, j, trees)

print (math.floor(ways))
    

Test 1

Group: 1

Verdict: ACCEPTED

Test 2

Group: 1

Verdict: ACCEPTED

Test 3

Group: 1

Verdict: ACCEPTED

Test 4

Group: 1

Verdict: ACCEPTED

Test 5

Group: 1

Verdict: ACCEPTED

Test 6

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 7

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 8

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 9

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 10

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 11

Group: 3

Verdict: TIME LIMIT EXCEEDED

Test 12

Group: 3

Verdict: TIME LIMIT EXCEEDED

Test 13

Group: 3

Verdict: TIME LIMIT EXCEEDED

Test 14

Group: 3

Verdict: TIME LIMIT EXCEEDED

Test 15

Group: 3

Verdict: TIME LIMIT EXCEEDED