Jun 21, 2022 · May 21, 2022 · May 22, 2022 · Jun 21, 2022 · Jun 21, 2022
diff --git a/problems/0042.接雨水.md b/problems/0042.接雨水.md
Original file line number	Diff line number	Diff line change
Expand Up		@@ -744,6 +744,91 @@ var trap = function(height) {
		};
		```

	### TypeScript

	双指针法:

	```typescript
	function trap(height: number[]): number {
	const length: number = height.length;
	let resVal: number = 0;
	for (let i = 0; i < length; i++) {
	let leftMaxHeight: number = height[i],
	rightMaxHeight: number = height[i];
	let leftIndex: number = i - 1,
	rightIndex: number = i + 1;
	while (leftIndex >= 0) {
	if (height[leftIndex] > leftMaxHeight)
	leftMaxHeight = height[leftIndex];
	leftIndex--;
	}
	while (rightIndex < length) {
	if (height[rightIndex] > rightMaxHeight)
	rightMaxHeight = height[rightIndex];
	rightIndex++;
	}
	resVal += Math.min(leftMaxHeight, rightMaxHeight) - height[i];
	}
	return resVal;
	};
	```

	动态规划:

	```typescript
	function trap(height: number[]): number {
	const length: number = height.length;
	const leftMaxHeightDp: number[] = [],
	rightMaxHeightDp: number[] = [];
	leftMaxHeightDp[0] = height[0];
	rightMaxHeightDp[length - 1] = height[length - 1];
	for (let i = 1; i < length; i++) {
	leftMaxHeightDp[i] = Math.max(height[i], leftMaxHeightDp[i - 1]);
	}
	for (let i = length - 2; i >= 0; i--) {
	rightMaxHeightDp[i] = Math.max(height[i], rightMaxHeightDp[i + 1]);
	}
	let resVal: number = 0;
	for (let i = 0; i < length; i++) {
	resVal += Math.min(leftMaxHeightDp[i], rightMaxHeightDp[i]) - height[i];
	}
	return resVal;
	};
	```

	单调栈:

	```typescript
	function trap(height: number[]): number {
	const length: number = height.length;
	const stack: number[] = [];
	stack.push(0);
	let resVal: number = 0;
	for (let i = 1; i < length; i++) {
	let top = stack[stack.length - 1];
	if (height[top] > height[i]) {
	stack.push(i);
	} else if (height[top] === height[i]) {
	stack.pop();
	stack.push(i);
	} else {
	while (stack.length > 0 && height[top] < height[i]) {
	let mid = stack.pop();
	if (stack.length > 0) {
	let left = stack[stack.length - 1];
	let h = Math.min(height[left], height[i]) - height[mid];
	let w = i - left - 1;
	resVal += h * w;
	top = stack[stack.length - 1];
	}
	}
	stack.push(i);
	}
	}
	return resVal;
	};
	```

		### C:

		一种更简便的双指针方法:
Expand Down