Both are Two Pointers

11. Container With Most Water

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
public int maxArea(int[] height) {
	int i = 0;
	int j = height.length-1;
	int res = 0;
	while(i < j){
		//面积
		int tmp = (j-i) * Math.min(height[i], height[j]);
		res = Math.max(res, tmp);
		if(height[i] > height[j]){
			j--;
		}else{
			i++;
		}
	}
	return res;
}

42. Trapping Rain Water

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
public int trap(int[] height) {
int i = 0;
int j = height.length - 1;
//记录当前最大高度
int curh = 0;
//记录每个值的高度
int[] res = new int[height.length];
while (i <= j) {
	if (height[i] > height[j]) {
		// curh = Math.max(curh, height[i]);
		curh = Math.max(curh, height[j]);
		res[j] = curh;
		j--;
	} else if (height[i] < height[j]) {
		curh = Math.max(curh, height[i]);
		res[i] = curh;
		i++;
	} else {
		curh = Math.max(curh, height[i]);
		res[i] = curh;
		res[j] = curh;
		i++;
		j--;
	}
}
int cnt = 0;
for (int k = 0; k < height.length; k++) {
	cnt += (res[k] - height[k]);
}
return cnt;
}

More Reference

11. Container With Most Water
42. Trapping Rain Water