dp

Author: vegetabledogg

303-Range-Sum-Query-Immutable.c

@@ -0,0 +1,49 @@
+typedef struct {
+    int numsSize;
+    int *nums;
+    int *sums;
+} NumArray;
+
+NumArray* numArrayCreate(int* nums, int numsSize) {
+    NumArray *newArray = (NumArray*)malloc(sizeof(NumArray));
+    newArray->numsSize  = numsSize;
+    newArray->nums = nums;
+    newArray->sums = (int*)calloc(numsSize, sizeof(int));
+    for (int i = 0; i < numsSize; i++)
+    {
+        if (0 == i)
+        {
+            newArray->sums[i] = nums[i];
+        }
+        else
+        {
+            newArray->sums[i] = newArray->sums[i - 1] + nums[i];
+        }
+    }
+    return newArray;
+}
+
+int numArraySumRange(NumArray* obj, int i, int j) {
+    int sum = 0;
+    if (0 > i)
+    {
+        i = 0;
+    }
+    if (j > obj->numsSize - 1)
+    {
+        j = obj->numsSize - 1;
+    }
+    return obj->sums[j] - obj->sums[i] + obj->nums[i];
+}
+
+void numArrayFree(NumArray* obj) {
+    free(obj->nums);
+    free(obj);
+}
+
+/**
+ * Your NumArray struct will be instantiated and called as such:
+ * struct NumArray* obj = numArrayCreate(nums, numsSize);
+ * int param_1 = numArraySumRange(obj, i, j);
+ * numArrayFree(obj);
+ */