Problem:
There is a rectangle in the xy-plane, with its lower left corner at (0, 0) and its upper right corner at (W, H). Each of its sides is parallel to the x-axis or y-axis. Initially, the whole region within the rectangle is painted white.  Snuke plotted N points into the rectangle. The coordinate of the i-th (1 ≦ i ≦ N) point was (x_i, y_i).  Then, he created an integer sequence a of length N, and for each 1 ≦ i ≦ N, he painted some region within the rectangle black, as follows:    * If a_i = 1, he painted the region satisfying x < x_i within the rectangle.   * If a_i = 2, he painted the region satisfying x > x_i within the rectangle.   * If a_i = 3, he painted the region satisfying y < y_i within the rectangle.   * If a_i = 4, he painted the region satisfying y > y_i within the rectangle.  Find the area of the white region within the rectangle after he finished painting.

Incorrect submission (verdict: Wrong Answer):
#









#
import sys
sys.setrecursionlimit(10**6)
input=sys.stdin.readline
from math import floor,ceil,sqrt,factorial,log 
from heapq import heappop, heappush, heappushpop
from collections import Counter,defaultdict,deque
from itertools import accumulate,permutations,combinations,product,combinations_with_replacement
from bisect import bisect_left,bisect_right
from copy import deepcopy
inf=float('inf')
mod = 10**9+7
def pprint(*A): 
    for a in A:     print(*a,sep='\n')
def INT_(n): return int(n)-1
def MI(): return map(int,input().split())
def MF(): return map(float, input().split())
def MI_(): return map(INT_,input().split())
def LI(): return list(MI())
def LI_(): return [int(x) - 1 for x in input().split()]
def LF(): return list(MF())
def LIN(n:int): return [I() for _ in range(n)]
def LLIN(n: int): return [LI() for _ in range(n)]
def LLIN_(n: int): return [LI_() for _ in range(n)]
def LLI(): return [list(map(int, l.split() )) for l in input()]
def I(): return int(input())
def F(): return float(input())
def ST(): return input().replace('\n', '')
def main():
    W,H,N = MI()
    bottom = 0
    top = H
    left = 0
    right = W
    print(right)
    for i in range(N):
        a,b,c = MI()
        if c==1:
            left = max(left,a)
        if c==2:
            right = min(right,a)
        if c==3:
            bottom = max(bottom, b)
        if c==4:
            top = min(top, b)
    print((right-left)*(top-bottom))
if __name__ == '__main__':
    main()

Fixed, accepted submission:
#









#
import sys
sys.setrecursionlimit(10**6)
input=sys.stdin.readline
from math import floor,ceil,sqrt,factorial,log 
from heapq import heappop, heappush, heappushpop
from collections import Counter,defaultdict,deque
from itertools import accumulate,permutations,combinations,product,combinations_with_replacement
from bisect import bisect_left,bisect_right
from copy import deepcopy
inf=float('inf')
mod = 10**9+7
def pprint(*A): 
    for a in A:     print(*a,sep='\n')
def INT_(n): return int(n)-1
def MI(): return map(int,input().split())
def MF(): return map(float, input().split())
def MI_(): return map(INT_,input().split())
def LI(): return list(MI())
def LI_(): return [int(x) - 1 for x in input().split()]
def LF(): return list(MF())
def LIN(n:int): return [I() for _ in range(n)]
def LLIN(n: int): return [LI() for _ in range(n)]
def LLIN_(n: int): return [LI_() for _ in range(n)]
def LLI(): return [list(map(int, l.split() )) for l in input()]
def I(): return int(input())
def F(): return float(input())
def ST(): return input().replace('\n', '')
def main():
    W,H,N = MI()
    bottom = 0
    top = H
    left = 0
    right = W
    for i in range(N):
        a,b,c = MI()
        if c==1:
            left = max(left,a)
        if c==2:
            right = min(right,a)
        if c==3:
            bottom = max(bottom, b)
        if c==4:
            top = min(top, b)
    if left <= right and bottom <= top:
        print((right-left)*(top-bottom))
    else:
        print(0)
if __name__ == '__main__':
    main()