35 lines
1.2 KiB
Plaintext
35 lines
1.2 KiB
Plaintext
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class Solution {
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public int numSubmatrixSumTarget(int[][] matrix, int target) {
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int xLength = matrix.length;
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int yLength = matrix[0].length;
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int[][] sum = new int[xLength + 1][yLength + 1];
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Map<Integer, Integer> map = new HashMap<>();
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int count = 0;
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for (int i = 1; i < xLength + 1; i++) {
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for (int j = 1; j < yLength + 1; j++) {
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sum[i][j] = sum[i - 1][j] + sum[i][j - 1] - sum[i - 1][j - 1];
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if (matrix[i - 1][j - 1] == target) {
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count++;
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}
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map.put(sum[i][j], map.getOrDefault(sum[i][j], 0));
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}
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}
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for (int key : map.keySet()) {
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int value = map.get(key);
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if (key == 2 * target && value > 1) {
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count += value * (value - 1) / 2;
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} else if (key > target && map.containsKey(key - target)) {
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count += value * map.get(key - target);
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}
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}
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return count;
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}
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}
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//total_testcases:40
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//total_correct:3
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//input_formatted:[[1,-1],[-1,1]]
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0
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//expected_output:5
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//code_output:0
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