二維數組連續四個成績最大

一個二維數組20*20，找橫，豎，主對角線方向，次對角線方向上連續四個數乘積的最大值。

#include<stdio.h>
int Max(int a, int b) {
	return a > b ? a : b;
}
int main(void) {
	int v1, v2, v3, v4;
	int arr[20][20] = { { 8,2,22,97,38,15,0,40,0,75,4,5,7,78,52,12,50,77,91,8 },
	{ 49,49,99,40,17,81,18,57,60,87,17,40,98,43,69,48,4,56,62,0 },
	{ 81,49,31,73,55,79,14,29,93,71,40,67,53,88,30,3,49,13,36,65 },
	{ 52,70,95,23,4,60,11,42,69,24,68,56,1,32,56,71,37,2,36,91 },
	{ 22,31,16,71,51,67,63,89,41,92,36,54,22,40,40,28,66,33,13,80 },
	{ 24,47,32,60,99,3,45,2,44,75,33,53,78,36,84,20,35,17,12,50 },
	{ 32,98,81,28,64,23,67,10,26,38,40,67,59,54,70,66,18,38,64,70 },
	{ 67,26,20,68,2,62,12,20,95,63,94,39,63,8,40,91,66,49,94,21 },
	{ 24,55,58,5,66,73,99,26,97,17,78,78,96,83,14,88,34,89,63,72 },
	{ 21,36,23,9,75,0,76,44,20,45,35,14,0,61,33,97,34,31,33,95 },
	{ 78,17,53,28,22,75,31,67,15,94,3,80,4,62,16,14,9,53,56,92 },
	{ 16,39,5,42,96,35,31,47,55,58,88,24,0,17,54,24,36,29,85,57 },
	{ 86,56,0,48,35,71,89,7,5,44,44,37,44,60,21,58,51,54,17,58 },
	{ 19,80,81,68,5,94,47,69,28,73,92,13,86,52,17,77,4,89,55,40 },
	{ 4,52,8,83,97,35,99,16,7,97,57,32,16,26,26,79,33,27,98,66 },
	{ 88,36,68,87,57,62,20,72,3,46,33,67,46,55,12,32,63,93,53,69 },
	{ 4,42,16,73,38,25,39,11,24,94,72,18,8,46,29,32,40,62,76,36 },
	{ 20,69,36,41,72,30,23,88,34,62,99,69,82,67,59,85,74,4,36,16 },
	{ 20,73,35,29,78,31,90,1,74,31,49,71,48,86,81,16,23,57,5,54 },
	{ 1,70,54,71,83,51,54,69,16,92,33,48,61,43,52,1,89,19,67,48 } };
	int max = -1;
	int i = 0, j, tmp;
	//找出橫行共20*17組中的最大
	for (; i < 20; i++) {//i控制行
		for (j = 0; j < 17; j++) {//j控制列
			tmp = 1;
			for (int k = 0; k < 4; k++) {//連續的四個
				tmp *= arr[i][j + k];
			}
			if (tmp > max)
				max = tmp;
		}
	}
	v1 = max;
	printf("橫行最大:%d\n", v1);
	//找出豎列中的最大
	for (j = 0; j < 20; j++) {
		for (i = 0; i < 17; i++) {
			tmp = 1;
			for (int k = 0; k < 4; k++) {
				tmp *= arr[i + k][j];
			}
			if (tmp > max) {
				max = tmp;
			}
		}
	}
	v2 = max;
	printf("豎列最大:%d\n", v2);
	//主對角線方向，共17*17
	for (i = 0; i < 17; i++) {//i控制行，每次掃四行
		for (j = 0; j < 17; j++) {//j控制列，每次掃四列
			tmp = 1;
			for (int k = 0; k < 4; k++) {
				tmp *= arr[i + k][j + k];
			}
			if (tmp > max) {
				max = tmp;
			}
		}
	}
	v3 = max;
	printf("主對角線方向最大:%d\n", v3);
	//次對角線方向，共17*17
	for (i = 0; i <17; i++) {
		for (j = 19; j > 2; j--) {
			tmp = 1;
			for (int k = 0; k <4; k++) {
				tmp *= arr[i +k][j - k];
			}
			if (tmp > max) {
				max = tmp;
			}
		}
	}
	v4 = max;
	printf("次對角線方向最大:%d\n", v4);
	max = Max(Max(Max(v1, v2), v3), v4);
	printf("-----------最大：%d\n", max);
	return 0;
}