diff options
Diffstat (limited to 'target_sum.c')
-rw-r--r-- | target_sum.c | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/target_sum.c b/target_sum.c new file mode 100644 index 0000000..4b5ef94 --- /dev/null +++ b/target_sum.c @@ -0,0 +1,29 @@ +// 494. Target Sum +#include "leetcode.h" + +/* + * given an integer array 'nums' and an integer 'target'. you want to buildan + * expression out of numbers by adding oneof the symbols '+' and '-' before each + * integer in nums awnd then concatenate all the integers. for example if 'nums + * = [2,1]', you can adda '+' before '2' and '-' before '1' and concatenate them + * to build the expression '+2-1'. return the number of different + * expressionsthat you can build, which evaluates to 'target'. + */ + +int findTargetSumWays(int *nums, int numsSize, int target) { + if (numsSize == 1) { + if (nums[0] == target && nums[0] == -target) + return 2; + if (nums[0] == target || nums[0] == -target) + return 1; + return 0; + } + return findTargetSumWays(&nums[1], numsSize - 1, target + nums[0]) + + findTargetSumWays(&nums[1], numsSize - 1, target - nums[0]); +} + +int main() { + int n1[] = {1, 1, 1, 1, 1}, n2[] = {1}; + printf("%d\n", findTargetSumWays(n1, ARRAY_SIZE(n1), 3)); // expect: 5 + printf("%d\n", findTargetSumWays(n2, ARRAY_SIZE(n2), 1)); // expect: 1 +} |