contest38的签到题。我用了sort:
public class MaximumProduct {
public int maximumProduct(int[] nums) {
if (nums.length < 3) return 0;
if (nums.length == 3) return nums[0] * nums[1] * nums[2];
int len = nums.length;
Arrays.sort(nums);
// if (nums[1] >= 0) {
// return nums[len - 1] * nums[len - 2] * nums[len - 3];
// }
return Math.max(nums[0] * nums[1] * nums[len - 1], nums[len - 1] * nums[len - 2] * nums[len - 3]);
}
}
也可以用扫描：
public class Solution {
public int maximumProduct(int[] nums) {
int min1 = Integer.MAX_VALUE, min2 = Integer.MAX_VALUE;
int max1 = Integer.MIN_VALUE, max2 = Integer.MIN_VALUE, max3 = Integer.MIN_VALUE;
for (int n: nums) {
if (n <= min1) {
min2 = min1;
min1 = n;
} else if (n <= min2) { // n lies between min1 and min2
min2 = n;
}
if (n >= max1) { // n is greater than max1, max2 and max3
max3 = max2;
max2 = max1;
max1 = n;
} else if (n >= max2) { // n lies betweeen max1 and max2
max3 = max2;
max2 = n;
} else if (n >= max3) { // n lies betwen max2 and max3
max3 = n;
}
}
return Math.max(min1 * min2 * max1, max1 * max2 * max3);
}
}
