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| 1 | +// Source : https://leetcode.com/problems/maximum-distance-between-a-pair-of-values/ |
| 2 | +// Author : Hao Chen |
| 3 | +// Date : 2021-05-09 |
| 4 | + |
| 5 | +/***************************************************************************************************** |
| 6 | + * |
| 7 | + * You are given two non-increasing 0-indexed integer arrays nums1 and nums2. |
| 8 | + * |
| 9 | + * A pair of indices (i, j), where 0 <= i < nums1.length and 0 <= j < nums2.length, is valid if both i |
| 10 | + * <= j and nums1[i] <= nums2[j]. The distance of the pair is j - i. |
| 11 | + * |
| 12 | + * Return the maximum distance of any valid pair (i, j). If there are no valid pairs, return 0. |
| 13 | + * |
| 14 | + * An array arr is non-increasing if arr[i-1] >= arr[i] for every 1 <= i < arr.length. |
| 15 | + * |
| 16 | + * Example 1: |
| 17 | + * |
| 18 | + * Input: nums1 = [55,30,5,4,2], nums2 = [100,20,10,10,5] |
| 19 | + * Output: 2 |
| 20 | + * Explanation: The valid pairs are (0,0), (2,2), (2,3), (2,4), (3,3), (3,4), and (4,4). |
| 21 | + * The maximum distance is 2 with pair (2,4). |
| 22 | + * |
| 23 | + * Example 2: |
| 24 | + * |
| 25 | + * Input: nums1 = [2,2,2], nums2 = [10,10,1] |
| 26 | + * Output: 1 |
| 27 | + * Explanation: The valid pairs are (0,0), (0,1), and (1,1). |
| 28 | + * The maximum distance is 1 with pair (0,1). |
| 29 | + * |
| 30 | + * Example 3: |
| 31 | + * |
| 32 | + * Input: nums1 = [30,29,19,5], nums2 = [25,25,25,25,25] |
| 33 | + * Output: 2 |
| 34 | + * Explanation: The valid pairs are (2,2), (2,3), (2,4), (3,3), and (3,4). |
| 35 | + * The maximum distance is 2 with pair (2,4). |
| 36 | + * |
| 37 | + * Example 4: |
| 38 | + * |
| 39 | + * Input: nums1 = [5,4], nums2 = [3,2] |
| 40 | + * Output: 0 |
| 41 | + * Explanation: There are no valid pairs, so return 0. |
| 42 | + * |
| 43 | + * Constraints: |
| 44 | + * |
| 45 | + * 1 <= nums1.length <= 10^5 |
| 46 | + * 1 <= nums2.length <= 10^5 |
| 47 | + * 1 <= nums1[i], nums2[j] <= 10^5 |
| 48 | + * Both nums1 and nums2 are non-increasing. |
| 49 | + ******************************************************************************************************/ |
| 50 | + |
| 51 | +classSolution { |
| 52 | +public: |
| 53 | +intmaxDistance(vector<int>& nums1, vector<int>& nums2) { |
| 54 | +returnmaxDistance2(nums1, nums2); |
| 55 | +returnmaxDistance1(nums1, nums2); |
| 56 | + } |
| 57 | + |
| 58 | + |
| 59 | +intbinary_search(vector<int>& nums,int start,int target) { |
| 60 | +int end = nums.size() -1; |
| 61 | +while (start <= end) { |
| 62 | +int mid = start + (end - start) /2; |
| 63 | +if(nums[mid] < target) end = mid -1; |
| 64 | +else start = mid+1; |
| 65 | + } |
| 66 | +return end; |
| 67 | + } |
| 68 | + |
| 69 | +intmaxDistance1(vector<int>& nums1, vector<int>& nums2) { |
| 70 | +intmDist=0; |
| 71 | +int right = nums2.size() -1; |
| 72 | +for(int i=0; i<nums1.size(); i++) { |
| 73 | +int j =binary_search(nums2, i, nums1[i]); |
| 74 | +mDist =max(mDist, j-i); |
| 75 | + } |
| 76 | +returnmDist; |
| 77 | + } |
| 78 | + |
| 79 | +intmaxDistance2(vector<int>& nums1, vector<int>& nums2) { |
| 80 | +int i=0, j=0, dist =0; |
| 81 | +while (i < nums1.size() && j < nums2.size() ){ |
| 82 | +if ( nums1[i] > nums2[j] ) i++; |
| 83 | +else dist =max(dist, j++ - i); |
| 84 | + } |
| 85 | +return dist; |
| 86 | + } |
| 87 | +}; |