1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
|
// 3356. Zero Array Transformation II
#include "leetcode.h"
/*
* you are given an integer array 'nums' of length 'n' and a 2d array 'queries'
* where 'queries[i] [l_i, r_i, val_i]'. each 'queries[i]' represents the
* following action on 'nums': decrement the value at each index in the range
* '[l_i, r_i]' in 'nums' by at most 'val_i'. the amount by which each value is
* decremented can be chosen independently for each index. a zero array is an
* array with all its elements equal to 0. return the minimum possible
* non-negative value of 'k', such that after processing the first 'k' queries
* in sequence, 'nums' becomes a zero array. if no such 'k' exists, return -1.
*/
bool can_cover(int *nums, int n, int **queries, int k) {
int *diff = (int *)calloc(n + 1, sizeof(int));
for (int i = 0; i < k; i++) {
int l = queries[i][0];
int r = queries[i][1];
int val = queries[i][2];
diff[l] += val;
if (r + 1 < n)
diff[r + 1] -= val;
}
int sum = 0;
for (int i = 0; i < n; i++) {
sum += diff[i];
if (sum < nums[i]) {
free(diff);
return false;
}
}
free(diff);
return true;
}
int minZeroArray(int *nums, int numsSize, int **queries, int queriesSize,
int *queriesColSize) {
int already_zero = 1;
for (int i = 0; i < numsSize; i++)
if (nums[i]) {
already_zero = 0;
break;
}
if (already_zero)
return 0;
int l = 1, r = queriesSize, ans = -1;
while (l <= r) {
int mid = l + (r - l) / 2;
if (can_cover(nums, numsSize, queries, mid)) {
ans = mid;
r = mid - 1;
} else
l = mid + 1;
}
return ans;
}
int main() {
int n1[] = {2, 0, 2}, q1i[3][3] = {{0, 2, 1}, {0, 2, 1}, {1, 1, 3}};
int n2[] = {4, 3, 2, 1}, q2i[2][3] = {{1, 3, 2}, {0, 2, 1}};
struct two_d_arr q1, q2;
two_d_arr_init(&q1, ARRAY_SIZE(q1i), ARRAY_SIZE(q1i[0]), q1i);
two_d_arr_init(&q2, ARRAY_SIZE(q2i), ARRAY_SIZE(q2i[0]), q2i);
printf("%d\n", minZeroArray(n1, ARRAY_SIZE(n1), q1.arr, q1.row_size,
q1.col_size)); // expect: 2
printf("%d\n", minZeroArray(n2, ARRAY_SIZE(n2), q2.arr, q2.row_size,
q2.col_size)); // expect: -1
two_d_arr_free(&q1);
two_d_arr_free(&q2);
}
|