1 files changed, 9 insertions, 0 deletions
diff --git a/progs/a100.py b/progs/a100.py
new file mode 100644
index 0000000..9236c70
--- /dev/null
+++ b/progs/a100.py
@@ -0,0 +1,9 @@
+def equilibrium_index(arr):
+  total_sum = sum(arr)
+  left_sum=0
+  for i, num in enumerate(arr):
+    total_sum -= num
+    if left_sum == total_sum:
+      return i
+    left_sum += num
+  return -1
+\ No newline at end of file