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// 330. Patching Array
#include "leetcode.h"
/*
* given a sorted integer array 'nums' and an integer 'n', add/patch elements to
* the array such that any number in the range '[1, n]' inclusive can be formed
* by the sum of some elements in the array. return the minimum number of
* patches required.
*/
int leading_bit(int n) {
int pos = -1;
for (int i = 0; i < 32; i++) {
if ((n & 1) == 1)
pos = i;
n >>= 1;
}
return pos;
}
int minPatches(int *nums, int numsSize, int n) {
int cnt = 0;
long long reachable = 1;
if (!numsSize)
return leading_bit(n) + 1;
if (numsSize == 1)
return leading_bit(n);
if (nums[0] != 1)
cnt++;
int i = 1 - cnt;
while (i < numsSize && reachable < n) {
if (nums[i] <= reachable + 1) {
reachable += nums[i];
i++;
} else {
cnt++;
reachable += reachable + 1;
}
if (reachable >= n)
return cnt;
}
while (reachable < n) {
reachable += reachable + 1;
cnt++;
}
return cnt;
}
int main() {
int n1[] = {1, 3}, n2[] = {1, 5, 10}, n3[] = {1, 2, 2};
printf("%d\n", minPatches(n1, ARRAY_SIZE(n1), 6)); // expect: 1
printf("%d\n", minPatches(n2, ARRAY_SIZE(n2), 20)); // expect: 2
printf("%d\n", minPatches(n3, ARRAY_SIZE(n3), 5)); // expect: 0
}
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