// 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 }