XOR Queries of a Subarray
给一个数组和一个queries数组, 让返回一个数组, 是queries中范围的xor值. 这个题就是pre sum.
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class Solution { public int[] xorQueries(int[] arr, int[][] queries) { for(int i = 1; i < arr.length; i++) { arr[i] = arr[i] ^ arr[i-1]; } int[] res = new int[queries.length]; for(int i = 0; i < queries.length; i++) { if(queries[i][0] > 0) res[i] = arr[queries[i][1]] ^ arr[queries[i][0]-1]; else res[i] = arr[queries[i][1]]; } return res; } } |