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| Original file line number | Diff line number | Diff line change |
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| @@ -0,0 +1 @@ | ||
| add_catch(test_binary_subarrays_with_sum test.cpp) |
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| Original file line number | Diff line number | Diff line change |
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| @@ -0,0 +1,54 @@ | ||
| #pragma once | ||
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| #include <unordered_map> | ||
| #include <vector> | ||
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| // Time: O(N) | ||
| // Space: O(1) | ||
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| namespace ps { | ||
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| // Time: O(N) | ||
| // Space: O(N) | ||
| class Solution { | ||
| public: | ||
| static int numSubarraysWithSum(const std::vector<int> &nums, int goal) { | ||
| int ans = 0; | ||
| std::unordered_map<int, int> map{{0, 1}}; | ||
| for (int sum = 0; auto num : nums) { | ||
| sum += num; | ||
| if (auto it = map.find(sum - goal); it != map.end()) { | ||
| ans += it->second; | ||
| } | ||
| ++map[sum]; | ||
| } | ||
| return ans; | ||
| } | ||
| }; | ||
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| } // namespace ps | ||
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| namespace sw { | ||
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| // Time: O(N) | ||
| // Space: O(1) | ||
| class Solution { | ||
| public: | ||
| static int numSubarraysWithSum(const std::vector<int> &nums, int goal) { | ||
| int ans = 0; | ||
| int sum = 0, zeros = 0; | ||
| for (int l = 0, r = 0; r < std::ssize(nums); ++r) { | ||
| sum += nums[r]; | ||
| while (l < r && (sum > goal || nums[l] == 0)) { | ||
| zeros = nums[l] ? 0 : zeros + 1; | ||
| sum -= nums[l++]; | ||
| } | ||
| if (sum == goal) { | ||
| ans += 1 + zeros; | ||
| } | ||
| } | ||
| return ans; | ||
| } | ||
| }; | ||
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| } // namespace sw |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,38 @@ | ||
| #include <catch.hpp> | ||
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| #include <solution.hpp> | ||
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| TEST_CASE("Simple") { | ||
| struct TestCase { | ||
| std::vector<int> nums; | ||
| int goal; | ||
| int expected; | ||
| }; | ||
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| std::vector<TestCase> test_cases{ | ||
| { | ||
| .nums{1, 0, 1, 0, 1}, | ||
| .goal = 2, | ||
| .expected = 4, | ||
| }, | ||
| { | ||
| .nums{0, 0, 0, 0, 0}, | ||
| .goal = 0, | ||
| .expected = 15, | ||
| }, | ||
| }; | ||
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| SECTION("Prefix Sum") { | ||
| for (const auto &[nums, goal, expected] : test_cases) { | ||
| const auto actual = ps::Solution::numSubarraysWithSum(nums, goal); | ||
| REQUIRE(expected == actual); | ||
| } | ||
| } | ||
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| SECTION("Sliding Window") { | ||
| for (const auto &[nums, goal, expected] : test_cases) { | ||
| const auto actual = sw::Solution::numSubarraysWithSum(nums, goal); | ||
| REQUIRE(expected == actual); | ||
| } | ||
| } | ||
| } |