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| class Solution {
public static int trap(int[] height) {
int len = height.length;
int waterSum = 0;
int[] leftMax = new int[len];
int[] rightMax = new int[len];
for (int i = 1; i <len - 1; i++) {
leftMax[i] = Math.max(leftMax[i - 1], height[i - 1]);
}
for (int i = len - 2; i >= 0; i--) {
rightMax[i] = Math.max(rightMax[i + 1], height[i + 1]);
}
for (int i = 1; i < len - 1; i++) {
int water = height[i] > Math.min(leftMax[i], rightMax[i]) ?
0 : Math.min(leftMax[i], rightMax[i]) - height[i];
waterSum += water;
}
return waterSum;
}
}
|
