From 3b34f9a82a28e1540616237ffadfe4d612d0e786 Mon Sep 17 00:00:00 2001
From: Ivan Reshetnikov <ordinarydev@protonmail.com>
Date: Thu, 17 Nov 2022 16:56:24 +0500
Subject: [PATCH] Problem 223: Rectangle area

---
 problems/223-rectangle-area/Makefile  | 14 +++++++++++
 problems/223-rectangle-area/lib.c     | 35 +++++++++++++++++++++++++++
 problems/223-rectangle-area/lib.h     |  2 ++
 problems/223-rectangle-area/main.c    | 12 +++++++++
 problems/223-rectangle-area/readme.md | 14 +++++++++++
 5 files changed, 77 insertions(+)
 create mode 100644 problems/223-rectangle-area/Makefile
 create mode 100644 problems/223-rectangle-area/lib.c
 create mode 100644 problems/223-rectangle-area/lib.h
 create mode 100644 problems/223-rectangle-area/main.c
 create mode 100644 problems/223-rectangle-area/readme.md

diff --git a/problems/223-rectangle-area/Makefile b/problems/223-rectangle-area/Makefile
new file mode 100644
index 0000000..ab746c4
--- /dev/null
+++ b/problems/223-rectangle-area/Makefile
@@ -0,0 +1,14 @@
+all: lib.o main.o
+	gcc -Wall -o bin lib.o main.o
+
+lib.o: lib.c
+	gcc -c -Wall lib.c
+
+main.o: main.c
+	gcc -c -Wall main.c
+
+run:
+	./bin
+
+clean:
+	rm *.o bin
diff --git a/problems/223-rectangle-area/lib.c b/problems/223-rectangle-area/lib.c
new file mode 100644
index 0000000..caeee90
--- /dev/null
+++ b/problems/223-rectangle-area/lib.c
@@ -0,0 +1,35 @@
+#include "lib.h"
+
+int _findIntersection(int a_start, int a_end, int b_start, int b_end) {
+    // aaaa
+    //   bbbb
+    if (a_end > b_start && a_start <= b_start && a_end <= b_end)
+        return a_end - b_start;
+    //   aa
+    // bbbbbb
+    if (a_start >= b_start && a_end <= b_end)
+        return a_end - a_start;
+    //   aaaa
+    // bbbb
+    if (a_start >= b_start && a_start < b_end && a_end >= b_end)
+        return b_end - a_start;
+    // aaaaa
+    //  bb
+    if (b_start >= a_start && b_end <= a_end)
+        return b_end - b_start;
+    return 0;
+}
+
+int computeArea(int ax1, int ay1, int ax2, int ay2, int bx1, int by1, int bx2, int by2) {
+    // Area of the first rectangle
+    int a = (ax2 - ax1) * (ay2 - ay1);
+
+    // Area of the second rectangle
+    int b = (bx2 - bx1) * (by2 - by1);
+
+    // Find intersection
+    int x_intersection = _findIntersection(ax1, ax2, bx1, bx2);
+    int y_intersection = _findIntersection(ay1, ay2, by1, by2);
+
+    return a + b - x_intersection * y_intersection;
+}
diff --git a/problems/223-rectangle-area/lib.h b/problems/223-rectangle-area/lib.h
new file mode 100644
index 0000000..55cb74f
--- /dev/null
+++ b/problems/223-rectangle-area/lib.h
@@ -0,0 +1,2 @@
+#pragma once
+int computeArea(int ax1, int ay1, int ax2, int ay2, int bx1, int by1, int bx2, int by2);
diff --git a/problems/223-rectangle-area/main.c b/problems/223-rectangle-area/main.c
new file mode 100644
index 0000000..6cb5335
--- /dev/null
+++ b/problems/223-rectangle-area/main.c
@@ -0,0 +1,12 @@
+#include <stdio.h>
+#include "lib.h"
+
+int main() {
+    int res1 = computeArea(-3, 0, 3, 4, 0, -1, 9, 2);
+    printf("Test 1: %d\n", res1 == 45);
+
+    int res2 = computeArea(-2, -2, 2, 2, -2, -2, 2, 2);
+    printf("Test 2: %d\n", res2 == 16);
+
+    return 0;
+}
diff --git a/problems/223-rectangle-area/readme.md b/problems/223-rectangle-area/readme.md
new file mode 100644
index 0000000..1ab62c2
--- /dev/null
+++ b/problems/223-rectangle-area/readme.md
@@ -0,0 +1,14 @@
+# 223. Rectangle area
+
+[Leetcode](https://leetcode.com/problems/rectangle-area/)
+
+Given the coordinates of two rectilinear rectangles in a 2D plane,
+return the total area covered by the two rectangles.
+
+The first rectangle is defined by its
+bottom-left corner (ax1, ay1) and its
+top-right corner (ax2, ay2).
+
+The second rectangle is defined by its
+bottom-left corner (bx1, by1) and its
+top-right corner (bx2, by2).