init commit

archive/algorithm/leetcode/413.c

@@ -0,0 +1,34 @@
+int numberOfArithmeticSlices(int* A, int ASize) {
+    int *dp = malloc(sizeof(int) * ASize), ret = 0;
+    memset(dp, 0, sizeof(int) * ASize);
+    dp[0] = 0;
+    dp[1] = 0;
+    for (int i = 2; i < ASize; i++) {
+        if (A[i] - A[i - 1] == A[i - 1] - A[i - 2]) {
+            dp[i] = dp[i - 1]+1;
+        }
+    }
+    for(int i=2;i<ASize;i++){
+        ret+=dp[i];
+    }
+    return ret;
+}
+/*
+int numberOfArithmeticSlices(int* A, int ASize) {
+    if(ASize<3) return 0;
+    int pred = A[1]-A[0];
+    int i;
+    int sum = 0;
+    int count = 2;
+    for(i=2; i<ASize; i++) {
+        if(A[i]-A[i-1] == pred) count++;
+        else {
+            if(count>2) sum +=  count*(count-3)/2+1;
+            count = 2;
+            pred = A[i]-A[i-1];
+        }
+    }
+    if(count>2) sum +=  count*(count-3)/2+1;
+    return sum;
+}
+*/