69 lines
1.8 KiB
C++
69 lines
1.8 KiB
C++
#include <vector>
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#include <iostream>
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/**
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* 915. Partition Array into Disjoint Intervals
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*
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* Given an integer array nums, partition it into two (contiguous) subarrays left and right so that:
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* - Every element in left is less than or equal to every element in right.
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* - left and right are non-empty.
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* - left has the smallest possible size.
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* Return the length of left after such a partitioning.
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* Test cases are generated such that partitioning exists.
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*/
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class Solution {
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private:
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static int partitionDisjoint_1(const std::vector<int>& nums) {
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const int n = nums.size();
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std::vector<int> max_until(n), min_since(n);
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max_until[0] = nums[0];
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min_since[n - 1] = nums[n - 1];
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for (int i = 1; i < n; ++i)
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max_until[i] = std::max(max_until[i - 1], nums[i]);
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for (int i = n - 1; i--; )
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min_since[i] = std::min(min_since[i + 1], nums[i]);
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for (int i = 1; i < n; ++i)
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if (max_until[i - 1] <= min_since[i])
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return i;
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return -1;
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}
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static int partitionDisjoint_2(const std::vector<int>& nums) {
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const int n = nums.size();
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std::vector<int> min_since(n);
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min_since[n - 1] = nums[n - 1];
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for (int i = n - 1; i--; )
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min_since[i] = std::min(min_since[i + 1], nums[i]);
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int max_until = nums[0];
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for (int i = 1; i < n; ++i) {
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if (max_until <= min_since[i])
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return i;
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max_until = std::max(max_until, nums[i]);
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}
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return -1;
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}
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public:
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static int partitionDisjoint(const std::vector<int>& nums) {
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const int n = nums.size();
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std::vector<int> min_since(n);
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min_since[n - 1] = nums[n - 1];
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for (int i = n - 1; i--; )
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min_since[i] = std::min(min_since[i + 1], nums[i]);
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int max_until = 0;
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for (int i = 1; i < n; ++i)
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if ((max_until = std::max(max_until, nums[i - 1])) <= min_since[i])
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return i;
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return -1;
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}
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};
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int main() {
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std::cout << Solution::partitionDisjoint({1,1,1,0,6,12});
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// todo: METRIC
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return 0;
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}
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