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Commit a0a50c9

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Merge branch 'youngyangyang04:master' into master
2 parents 84f41f6 + c855948 commit a0a50c9

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4 files changed

+147
-36
lines changed

4 files changed

+147
-36
lines changed

‎problems/0098.验证二叉搜索树.md‎

Lines changed: 22 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -408,7 +408,28 @@ class Solution:
408408
return True
409409

410410
```
411-
## Go
411+
```python
412+
# 遵循Carl的写法,只添加了节点判断的部分
413+
class Solution:
414+
def isValidBST(self, root: TreeNode) -> bool:
415+
# method 2
416+
que, pre = [], None
417+
while root or que:
418+
while root:
419+
que.append(root)
420+
root = root.left
421+
root = que.pop()
422+
# 对第一个节点只做记录,对后面的节点进行比较
423+
if pre is None:
424+
pre = root.val
425+
else:
426+
if pre >= root.val: return False
427+
pre = root.val
428+
root = root.right
429+
return True
430+
```
431+
432+
## Go
412433

413434
```Go
414435
import "math"

‎problems/0101.对称二叉树.md‎

Lines changed: 0 additions & 35 deletions
Original file line numberDiff line numberDiff line change
@@ -437,41 +437,6 @@ class Solution:
437437
return True
438438
```
439439

440-
层序遍历
441-
442-
```python
443-
class Solution:
444-
def isSymmetric(self, root: TreeNode) -> bool:
445-
if not root: return True
446-
que, cnt = [[root.left, root.right]], 1
447-
while que:
448-
nodes, tmp, sign = que.pop(), [], False
449-
for node in nodes:
450-
if not node:
451-
tmp.append(None)
452-
tmp.append(None)
453-
else:
454-
if node.left:
455-
tmp.append(node.left)
456-
sign = True
457-
else:
458-
tmp.append(None)
459-
if node.right:
460-
tmp.append(node.right)
461-
sign = True
462-
else:
463-
tmp.append(None)
464-
p1, p2 = 0, len(nodes) - 1
465-
while p1 < p2:
466-
if (not nodes[p1] and nodes[p2]) or (nodes[p1] and not nodes[p2]): return False
467-
elif nodes[p1] and nodes[p2] and nodes[p1].val != nodes[p2].val: return False
468-
p1 += 1
469-
p2 -= 1
470-
if sign: que.append(tmp)
471-
cnt += 1
472-
return True
473-
```
474-
475440
## Go
476441

477442
```go

‎problems/0332.重新安排行程.md‎

Lines changed: 44 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -506,6 +506,50 @@ var findItinerary = function(tickets) {
506506
507507
```
508508

509+
### TypeScript
510+
511+
```typescript
512+
function findItinerary(tickets: string[][]): string[] {
513+
/**
514+
TicketsMap 实例:
515+
{ NRT: Map(1) { 'JFK' => 1 }, JFK: Map(2) { 'KUL' => 1, 'NRT' => 1 } }
516+
这里选择Map数据结构的原因是:与Object类型的一个主要差异是,Map实例会维护键值对的插入顺序。
517+
*/
518+
type TicketsMap = {
519+
[index: string]: Map<string, number>
520+
};
521+
tickets.sort((a, b) => {
522+
return a[1] < b[1] ? -1 : 1;
523+
});
524+
const ticketMap: TicketsMap = {};
525+
for (const [from, to] of tickets) {
526+
if (ticketMap[from] === undefined) {
527+
ticketMap[from] = new Map();
528+
}
529+
ticketMap[from].set(to, (ticketMap[from].get(to) || 0) + 1);
530+
}
531+
const resRoute = ['JFK'];
532+
backTracking(tickets.length, ticketMap, resRoute);
533+
return resRoute;
534+
function backTracking(ticketNum: number, ticketMap: TicketsMap, route: string[]): boolean {
535+
if (route.length === ticketNum + 1) return true;
536+
const targetMap = ticketMap[route[route.length - 1]];
537+
if (targetMap !== undefined) {
538+
for (const [to, count] of targetMap.entries()) {
539+
if (count > 0) {
540+
route.push(to);
541+
targetMap.set(to, count - 1);
542+
if (backTracking(ticketNum, ticketMap, route) === true) return true;
543+
targetMap.set(to, count);
544+
route.pop();
545+
}
546+
}
547+
}
548+
return false;
549+
}
550+
};
551+
```
552+
509553
### Swift
510554

511555
直接迭代tickets数组:

‎problems/回溯算法去重问题的另一种写法.md‎

Lines changed: 81 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -365,6 +365,87 @@ class Solution:
365365
return res
366366
```
367367

368+
TypeScript:
369+
370+
**90.子集II**
371+
372+
```typescript
373+
function subsetsWithDup(nums: number[]): number[][] {
374+
nums.sort((a, b) => a - b);
375+
const resArr: number[][] = [];
376+
backTraking(nums, 0, []);
377+
return resArr;
378+
function backTraking(nums: number[], startIndex: number, route: number[]): void {
379+
resArr.push(route.slice());
380+
const helperSet: Set<number> = new Set();
381+
for (let i = startIndex, length = nums.length; i < length; i++) {
382+
if (helperSet.has(nums[i])) continue;
383+
helperSet.add(nums[i]);
384+
route.push(nums[i]);
385+
backTraking(nums, i + 1, route);
386+
route.pop();
387+
}
388+
}
389+
};
390+
```
391+
392+
**40. 组合总和 II**
393+
394+
```typescript
395+
function combinationSum2(candidates: number[], target: number): number[][] {
396+
candidates.sort((a, b) => a - b);
397+
const resArr: number[][] = [];
398+
backTracking(candidates, target, 0, 0, []);
399+
return resArr;
400+
function backTracking(
401+
candidates: number[], target: number,
402+
curSum: number, startIndex: number, route: number[]
403+
) {
404+
if (curSum > target) return;
405+
if (curSum === target) {
406+
resArr.push(route.slice());
407+
return;
408+
}
409+
const helperSet: Set<number> = new Set();
410+
for (let i = startIndex, length = candidates.length; i < length; i++) {
411+
let tempVal: number = candidates[i];
412+
if (helperSet.has(tempVal)) continue;
413+
helperSet.add(tempVal);
414+
route.push(tempVal);
415+
backTracking(candidates, target, curSum + tempVal, i + 1, route);
416+
route.pop();
417+
418+
}
419+
}
420+
};
421+
```
422+
423+
**47. 全排列 II**
424+
425+
```typescript
426+
function permuteUnique(nums: number[]): number[][] {
427+
const resArr: number[][] = [];
428+
const usedArr: boolean[] = [];
429+
backTracking(nums, []);
430+
return resArr;
431+
function backTracking(nums: number[], route: number[]): void {
432+
if (nums.length === route.length) {
433+
resArr.push(route.slice());
434+
return;
435+
}
436+
const usedSet: Set<number> = new Set();
437+
for (let i = 0, length = nums.length; i < length; i++) {
438+
if (usedArr[i] === true || usedSet.has(nums[i])) continue;
439+
usedSet.add(nums[i]);
440+
route.push(nums[i]);
441+
usedArr[i] = true;
442+
backTracking(nums, route);
443+
usedArr[i] = false;
444+
route.pop();
445+
}
446+
}
447+
};
448+
```
368449

369450
Go:
370451

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