Best time to buy and sell stock

begeekmyfriend · begeekmyfriend · commit e6b82a9707e4 · 2017-11-09T18:08:17.000+08:00
Signed-off-by: begeekmyfriend &lt;begeekmyfriend@gmail.com&gt;
diff --git a/123_best_time_to_buy_and_sell_stock_iii/Makefile b/123_best_time_to_buy_and_sell_stock_iii/Makefile
@@ -0,0 +1,2 @@
+all:
+	gcc -O2 -o test stock.c
diff --git a/123_best_time_to_buy_and_sell_stock_iii/stock.c b/123_best_time_to_buy_and_sell_stock_iii/stock.c
@@ -0,0 +1,48 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+static int maxProfit(int* prices, int pricesSize)
+{
+    if (pricesSize == 0) {
+        return 0;
+    }
+
+    int i, tmp, diff = 0, min = prices[0];
+    int *left_profit = malloc(pricesSize * sizeof(int));
+    for (i = 1; i < pricesSize; i++) {
+        if (prices[i] < min) {
+            min = prices[i];
+        } else {
+            tmp = prices[i] - min;
+            diff = tmp > diff ? tmp : diff;
+        }
+        left_profit[i] = diff;
+    }
+
+    int right_profit = 0;
+    int max = prices[pricesSize - 1];
+    int total = left_profit[pricesSize - 1];
+    for (i = pricesSize - 2; i >= 0; i--) {
+        if (prices[i] > max) {
+             max = prices[i];
+        } else {
+            tmp = max - prices[i];
+            right_profit = tmp > right_profit ? tmp : right_profit;
+        }
+        tmp = left_profit[i] + right_profit;
+        total = tmp > total ? tmp : total;
+    }
+
+    return total;
+}
+
+int main(int argc, char **argv)
+{
+    int i, count = argc - 1;
+    int *nums = malloc(count * sizeof(int));
+    for (i = 0; i < count; i++) {
+        nums[i] = atoi(argv[i + 1]);
+    }
+    printf("%d\n", maxProfit(nums, count));
+    return 0;
+}
