feat(leetcode): add 303 304 307

Author: man-fish

src/playground/leetcode/303range-sum-query-immutable/NumArray.ts

@@ -0,0 +1,14 @@
+export default class NumArray {
+    sumArray: number[];
+    constructor(nums: number[]) {
+        let n = nums.length;
+        this.sumArray = new Array(n + 1).fill(0);
+        for (let i = 0; i < n; i++) {
+            this.sumArray[i + 1] = this.sumArray[i] + nums[i];
+        }
+    }
+
+    sumRange(i: number, j: number): number {
+        return this.sumArray[j + 1] - this.sumArray[i];
+    }
+}

src/playground/leetcode/304range-sum-query-2d-immutable/NumMatrix.ts

@@ -0,0 +1,38 @@
+export default class NumMatrix {
+    store?: number[][];
+    constructor(matrix: number[][]) {
+        let n = matrix.length;
+        if (!n) return;
+        let m = matrix[0].length;
+        if (!m) return;
+        this.store = new Array(n + 1);
+        for (let i = 0; i < n + 1; i++) {
+            this.store[i] = new Array(m + 1).fill(0);
+        }
+
+        for (let i = 0; i < n; i++) {
+            for (let j = 0; j < m; j++) {
+                this.store[i + 1][j + 1] =
+                    matrix[i][j] +
+                    this.store[i][j + 1] +
+                    this.store[i + 1][j] -
+                    this.store[i][j];
+            }
+        }
+    }
+
+    sumRegion(row1: number, col1: number, row2: number, col2: number): number {
+        return this.store
+            ? this.store[row2 + 1][col2 + 1] -
+                  this.store[row1][col2 + 1] -
+                  this.store[row2 + 1][col1] +
+                  this.store[row1][col1]
+            : 0;
+    }
+}
+
+/**
+ * Your NumMatrix object will be instantiated and called as such:
+ * var obj = new NumMatrix(matrix)
+ * var param_1 = obj.sumRegion(row1,col1,row2,col2)
+ */

src/playground/leetcode/307range-sum-query-mutable/NumArray.ts

@@ -0,0 +1,31 @@
+export default class NumArray {
+    sumArray: number[];
+    nums: number[];
+    constructor(nums: number[]) {
+        let n = nums.length;
+        this.nums = nums;
+        this.sumArray = new Array(n + 1).fill(0);
+        for (let i = 0; i < n; i++) {
+            this.sumArray[i + 1] = this.sumArray[i] + nums[i];
+        }
+    }
+
+    sumRange(i: number, j: number): number {
+        return this.sumArray[j + 1] - this.sumArray[i];
+    }
+
+    update(i: number, val: number): void {
+        let sub = val - this.nums[i];
+        this.nums[i] = val;
+        for (i = i + 1; i < this.sumArray.length; i++) {
+            this.sumArray[i] += sub;
+        }
+    }
+}
+
+/**
+ * Your NumArray object will be instantiated and called as such:
+ * var obj = new NumArray(nums)
+ * obj.update(i,val)
+ * var param_2 = obj.sumRange(i,j)
+ */

src/playground/leetcode/342power-of-four/isPowerOfFour.ts

@@ -13,7 +13,8 @@ export default function isPowerOfFour(num: number): boolean {
     );
     /** 
         return (
-            (num > 0 && (num ^ 0x1) === 0) ||
+            (num > 0 && 
+            (num ^ 0x1) === 0) ||
             (num ^ 0x4) === 0 ||
             (num ^ 0x10) === 0 ||
             (num ^ 0x40) === 0 ||