資工趴趴熊的小天地

C++

/*
Input: nums = [-1,0,3,5,9,12], target = 9
Output: 4
Explanation: 9 exists in nums and its index is 4
*/ 

class Solution {
public:
    int search(vector<int>& nums, int target) {
        int left=0;
        int right=nums.size()-1;
        
        while(left<=right){
                int middle=left+((right-left)/2);//防止溢出
                        if(nums[middle]>target){
                                right=middle-1;
                        } 
                        else if(nums[middle]<target){
                                left=middle+1;
                        }
                        else return middle; //找到 
                }
                return -1; //未找到 
    }
};

python:

class Solution {
private:
        bool backtracking(vector<vector<char>>& board) {
                for (int i = 0; i < board.size(); i++){ //跑直得 
                        for (int j = 0; j < board[0].size(); j++){ //跑橫得 
                                if (board[i][j] != '.') continue; //不是要跑的空格，跑下個迴圈 
                                for (char k = '1'; k <= '9'; k++){ 
                                        if(isValid(i, j, k, board)){ // (i, j) 位置放k是否合適，若合適的話 
                                                board[i][j] = k; //就把數字填上去 
                                                if (backtracking(board)) return true; // 如果找到合适立刻返回
                        board[i][j] = '.'; // 回溯，
                                        } 
                                        
                                } 
                                return false; // 9個數字都不行，那么就返回false
                        } 
                }
                return true; // 跑完全不沒有返回false，就是找到答案了 
        }
        /*-----------------------------------------------------------------*/ 
        bool isValid(int row, int col, char val, vector<vector<char>>& board){
                //判斷橫的
                for (int i = 0; i < 9; i++) {
                if (board[row][i] == val) {
                return false;
                }
        } 
        
        //判斷直的
        for (int j = 0; j < 9; j++) { 
                if (board[j][col] == val) {
                    return false;
                }
            }
            
            //判斷小框框內9格是否重複 
            int startRow = (row / 3) * 3;  
            int startCol = (col / 3) * 3;
            for (int i = startRow; i < startRow + 3; i++) { 
                for (int j = startCol; j < startCol + 3; j++) {
                    if (board[i][j] == val ) {
                        return false;
                    }
                }
            }
            return true;
        } 
        
        
public:
    void solveSudoku(vector<vector<char>>& board) {
        backtracking(board);//引入函式 
        
        
    }
};

Given an array of integers nums and an integer target, return indices of the two numbers such that they add up to target.

You may assume that each input would have exactly one solution, and you may not use the same element twice.