二分，简单题
https://leetcode.cn/problems/binary-search/submissions/569521757/
```js
var search = function (nums, target) {
let left = 0, right = nums.length - 1;
while (left <= right) {
const center = Math.floor((left + right) / 2);
if (nums < target) {
left = center + 1
} else if (nums > target) {
right = center - 1
} else {
return center
}
}
return -1
};
```
https://leetcode.cn/problems/convert-binary-number-in-a-linked-list-to-integer/submissions/569521965/
链表基础题
```js
var getDecimalValue = function (head) {
let result = 0;
while (head !== null) {
result*=2;
result += head.val;
head=head.next
}
return result
};
```
https://leetcode.cn/problems/find-the-minimum-and-maximum-number-of-nodes-between-critical-points/submissions/569522962/
链表~秒了
```js
var nodesBetweenCriticalPoints = function (head) {
let firstNode = null;
let lastNode = null;
let lastVal = null;
let pos = -1;
let Max = -1;
let Min = Number.MAX_SAFE_INTEGER;
while (head !== null) {
pos++;
if (lastVal == null || head.next == null) {
lastVal = head.val;
head = head.next;
continue;
}
if ((lastVal < head.val && head.next.val < head.val) || (lastVal > head.val && head.next.val > head.val)) {
if (firstNode !== null) {
Max = pos - firstNode
} else {
firstNode = pos
}
if (lastNode !== null) {
Min = Math.min(Min, pos - lastNode)
lastNode = pos
} else {
lastNode = pos
}
}
lastVal=head.val;
head = head.next;
}
return
};
```
https://leetcode.cn/problems/merge-nodes-in-between-zeros/submissions/569523251/
接近百分百！
开心
```js
var mergeNodes = function (head) {
let ptr = head
while (head !== null) {
if (head.val == 0 && head.next !== null) {
while (head.next.next.val !== 0) {
head.next.val += head.next.next.val;
head.next.next = head.next.next.next;
}
}
head = head.next
}
ptr = ptr.next;
head = ptr
while (head !== null) {
if (head.next.val == 0) {
head.next=head.next.next
}
head = head.next
}
return ptr
};
```
https://leetcode.cn/problems/contains-duplicate-ii/submissions/569525278/
滑窗过了
偏简单的题
```js
var containsNearbyDuplicate = function (nums, k) {
const cache = new Map();
k=Math.min(nums.length,k)
for (let index = 0; index <= k; index++) {
const num = nums;
if (cache.has(num)) {
return true;
}
cache.set(num, index);
}
for (let index = k + 1; index < nums.length; index++) {
cache.delete(nums);
const num = nums;
if (cache.has(num)) {
return true;
}
cache.set(num, index);
}
return false;
};
```
https://leetcode.cn/problems/max-pair-sum-in-an-array/submissions/569525653/
基础哈希题
一次过
```js
var maxSum = function (nums) {
const cache = new Map();
let result = -1;
for (let index = 0; index < nums.length; index++) {
let num = nums;
let maxNum = 0;
while (num !== 0) {
const tailNum = num % 10;
num = Math.floor(num / 10);
maxNum = Math.max(maxNum, tailNum);
}
if (cache.has(maxNum)) {
const lastNum = cache.get(maxNum);
result = Math.max(result, lastNum + nums);
if (lastNum < nums) {
cache.set(maxNum, nums);
}
} else {
cache.set(maxNum, nums);
}
}
return result
};
```
https://leetcode.cn/problems/max-sum-of-a-pair-with-equal-sum-of-digits/submissions/569525779/
改改又过一题
```js
var maximumSum = function (nums) {
const cache = new Map();
let result = -1;
for (let index = 0; index < nums.length; index++) {
let num = nums;
let totalNum = 0;
while (num !== 0) {
const tailNum = num % 10;
num = Math.floor(num / 10);
totalNum = totalNum + tailNum;
}
if (cache.has(totalNum)) {
const lastNum = cache.get(totalNum);
result = Math.max(result, lastNum + nums);
if (lastNum < nums) {
cache.set(totalNum, nums);
}
} else {
cache.set(totalNum, nums);
}
}
return result;
};
```
https://leetcode.cn/problems/max-number-of-k-sum-pairs/submissions/569526086/
过了~
```js
var maxOperations = function (nums, k) {
const cache = new Map();
let result = 0;
for (let index = 0; index < nums.length; index++) {
let num = nums;
if (cache.has(k - num)) {
result++;
if (cache.get(k - num) == 1) {
cache.delete(k - num);
} else {
cache.set(k - num, cache.get(k - num) - 1);
}
} else {
cache.set(num, (cache.get(num) ?? 0) + 1);
}
}
return result;
};
```
https://leetcode.cn/problems/target-sum/submissions/569711739/
基础dp，dfs秒了
```js
var findTargetSumWays = function (nums, target) {
const cache = new Map()
const dfs = (index, rest) => {
const flag = `${index} ${rest}`
if (cache.has(flag)) {
return cache.get(flag)
}
if (index >= nums.length) {
return rest == 0 ? 1 : 0
}
const result = dfs(index + 1, rest + nums) + dfs(index + 1, rest - nums)
cache.set(flag, result);
return result
}
return dfs(0, target)
};
```
https://leetcode.cn/problems/longest-increasing-path-in-a-matrix/submissions/569712767/
递归缓存秒了
```js
var longestIncreasingPath = function (matrix) {
const cache = new Map()
const dfs = (posX, posY) => {
const flag = `${posX} ${posY}`
if (cache.has(flag)) {
return cache.get(flag)
}
const arr = [[-1, 0], , [+1, 0], ]
let result = 1;
for (let index = 0; index < arr.length; index++) {
const = arr;
const x = posX - relX;
const y = posY - relY
if (x >= matrix.length || x < 0 || y >= matrix.length || y < 0) {
continue;
}
if (matrix > matrix) {
result = Math.max(result, dfs(x, y) + 1)
}
}
cache.set(flag, result)
return result
}
let result = 0;
for (let index = 0; index < matrix.length; index++) {
for (let indey = 0; indey < matrix.length; indey++) {
const len = dfs(index, indey)
result = Math.max(result, len)
}
}
return result
};
```