Stay button --- 2020.3.18

836. rectangles overlap

class Solution {
    public boolean isRectangleOverlap(int[] rec1, int[] rec2) {
        if(rec2[1] >= rec1[3] || rec1[1] >= rec2[3]){
            return false;
        }
	    if(rec1[0] >= rec2[2] || rec1[2] <= rec2[0]){
	        return false;
        }
	  return true;
    }
}

class Solution {
    public boolean isRectangleOverlap(int[] rec1, int[] rec2) {
        return (Math.min(rec1[2], rec2[2]) > Math.max(rec1[0], rec2[0]) &&
                Math.min(rec1[3], rec2[3]) > Math.max(rec1[1], rec2[1]));
    }
}

17. The print face questions from 1 to the maximum number of bits n

class Solution {
    public int[] printNumbers(int n) {
        int x = (int)Math.pow(10,n);
        int[] res = new int[x-1];
        for(int i=0;i<x-1;i++){
            res[i] = i+1;
        }
        return res;
    }
}

class Solution {
    public int[] printNumbers(int n) {  
		String num ="";
		for(int i = 0 ; i <= n ;i++) {
			if(i == 0)
				num += "1";
			else
				num += "0";
		}
		int index = Integer.valueOf(num);
		int []reuslt = new int[--index];
		for(int i = 0 ; i < index ;i++) {
			reuslt[i] = i+1;
		}
		return reuslt;
    }
}

class Solution {
    public int[] printNumbers(int n) {
		//因为n为正整数，所以最小为10，也可以把10改为9，100改为99等
		int[] map = { 10, 100, 1000, 10_000, 100_000, 1_000_000, 10_000_000,
 				100_000_000, 1_000_000_000, Integer.MAX_VALUE };
		int size = map[n-1];
		int[] ans = new int[size - 1];
		for (int i = 1; i < size; i++) {
			ans[i - 1] = i;
		}
		return ans;
    }
}

class Solution {
    public int[] printNumbers(int n) {
        int temp = 1;
        for(int i=0;i<n;i++){
            temp *= 10;
        }
        int[] rec = new int[temp-1];
        int index=0;
        for(int k=1;k<temp;k++){
            rec[index] = k;
            index++;
        }
        return rec;
    }
}

Interview questions 56 - II digital frequency array appears II.

class Solution {
    public int singleNumber(int[] nums) {
        Arrays.sort(nums);
        for(int i=0;i<nums.length-2;i++){
            if(nums[i]==nums[i+1]&&nums[i+1]==nums[i+2]){
                i +=2;
            }else{
                return nums[i];
            }
        }
        return nums[nums.length-1];
    }
}

//还没搞懂...
class Solution {
    public int singleNumber(int[] nums) {
        int a = 0;
        int b = 0;
     
        for(int num : nums) {
        	a = (a ^ num) & ~b;
        	b = (b ^ num) & ~a;
        }
        
        return a;
    }
}

class Solution {
    public int singleNumber(int[] nums) {
        int ans = 0;
        //int 32位
        for(int i=0;i<32;i++){
            int count =0;
            for(int num:nums){
                if((num&(1<<i))!=0) count++;
            }
            if(count%3!=0) ans += 1<<i;
        }
        return ans;
    } 
}

class Solution {
    public int singleNumber(int[] nums) {
        Map<Integer,Integer> map=new HashMap<Integer,Integer>();
		for(int num:nums) {
			map.put(num, map.getOrDefault(num, 0)+1);
		}
		for(Object key:map.keySet()) {
			if(map.get(key).equals(1))  return (int) key;
		}
		return 0;
    }
}

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