debug info

Author: rw

justfile

@@ -1,2 +1,5 @@
 test:
     nix-instantiate --eval leetcode.nix | jq -r 'fromjson | .'
+
+wtest:
+    watch "nix-instantiate --eval leetcode.nix | jq -r 'fromjson | .'"

leetcode.nix

@@ -1,27 +1,27 @@
 #  nix-instantiate --eval leetcode.nix | jq -r 'fromjson | .'          
 
-let 
+let
   fac = self: acc: n: if n == 0 then acc else self (n * acc) (n - 1);
   pow2 = n: builtins.bitAnd n (n - 1) == 0;
   remainder = a: b:
     if a < b then a
     else remainder (a - b) b;
   sumDivisors = n: builtins.foldl'
-    (runningsum: current: 
+    (runningsum: current:
       if remainder n current == 0
-      then current + runningsum 
+      then current + runningsum
       else runningsum)
-    0 
-    (if n == 1 then [] else 
-      builtins.genList (x: x+1) (n - 2));   
+    0
+    (if n == 1 then [ ] else
+    builtins.genList (x: x + 1) (n - 2));
   # https://leetcode.com/problems/perfect-number/
-  perfectNumber = n: 
+  perfectNumber = n:
     if n < 6 then false
     else sumDivisors n == n;
   fib = n:
     if n == 0 then n else
     if n == 1 then n else
-    fib(n - 1)+fib(n - 2);
+    fib (n - 1) + fib (n - 2);
   fibTCO = self: acc: n:
     if n == 0 then acc else
     if n == 1 then acc else
@@ -30,71 +30,85 @@ let
   facTCO = n: tco fac 1 n;
   ftco = n: tco fibTCO 1 n;
   # https://leetcode.com/problems/take-gifts-from-the-richest-pile/
-  sqrt = number: iterations: 
-    let 
+  sqrt = number: iterations:
+    let
       nextGuess = guess: (guess + number / guess) / 2;
-      improve = guess: 
+      improve = guess:
         if iterations == 0 then guess
         else improve (nextGuess guess) (iterations - 1);
-    in improve 1 iterations;
+    in
+    improve 1 iterations;
   # https://leetcode.com/problems/two-sum/
-  twosum = nums: target:
-    let 
-      h = {};
-      add = (h: k: v: h // {k = v;});
-      get = (h: k: h.k);
-    in 
-      (builtins.foldl' 
-        (acc: num: 
-          let 
-            complement = target - num;
-          in 
-            if builtins.length acc.ans > 0 then acc
-            else
-            if builtins.hasAttr (builtins.toString complement) h
+  twosum = { nums, target, debug ? false}:
+    let
+      h = { };
+      add = (h: k: v: h // { k = v; });
+      impl = (builtins.foldl'
+        (acc: num:
+          let
+            comp = target - num;
+            complement = builtins.toString (comp);
+            exists = builtins.hasAttr complement h;
+            compAddsToTarget = exists && comp + num == target;
+          in
+          if builtins.length acc.ans > 0 then acc
+          else
+            if compAddsToTarget
             then acc // {
-              ans = [get h complement acc.i];
+              ans = [ h.${complement} acc.i ];
+              detected = true;
             }
             else acc // {
-              acc.h = add acc.h (builtins.toString complement) acc.i;
+              h = acc.h // {
+                ${complement} = acc.i;
+              };
               i = acc.i + 1;
+              nums = acc.nums ++ [ num ];
+              complements = acc.complements ++ [ complement ];
             }
         )
         {
           i = 0;
           h = h;
-          ans = [];
-
+          ans = [ ];
+          nums = [ ];
+          complements = [ ];
+          detected = false;
         }
-        nums).ans;
-
+        nums);
+    in
+    if debug then impl else impl.ans;
   # pickGifts = gifts: k:
 in
-  # using builtins.toJSON to eagerly evaluate the tests
+# using builtins.toJSON to eagerly evaluate the tests
   # jq then pretty prints the result
-  builtins.toJSON {
-    tests =[
-      (assert remainder 10 3 == 1; "remainder works")
-      (assert  perfectNumber 6; "six is perfect")
-      (assert ! perfectNumber 7; "seven is not perfect")
-      (assert pow2 33554432; "2^25 is a power of 2")
-      (assert fib 1 == 1; "fib 1 is 1")
-      (assert fib 2 == 1; "fib 2 is 1")
-      (assert fib 3 == 2; "fib 3 is 2")
-      (assert fib 4 == 3; "fib 4 is 3")
-      (assert fib 5 == 5; "fib 5 is 5")
-      (assert fib 6 == 8; "fib 6 is 8")
-      (assert facTCO 15 == 1307674368000; "tail call optimized factorial works")
-      (assert ftco 100 == 5050; "tail call optimized fibonacci works")
-      # # nums = [2,7,11,15], target = 9
-      # (assert twosum [2 7 11 15] 9 == [0 1]; "two sum works")
-      # # Input: nums = [3,2,4], target = 6
-      # # Output: [1,2]
-      # (assert twosum [3 2 4] 6 == [1 2]; "two sum works")
-      # # Input: nums = [3,3], target = 6
-      # # Output: [0,1]
-      # (assert twosum [3 3] 6 == [0 1]; "two sum works")
+builtins.toJSON {
+  twosum = twosum {
+    nums = [ 2 7 11 15 ];
+    target = 9;
+    debug = true;
+  };
+  tests = [
+    (assert remainder 10 3 == 1; "remainder works")
+    (assert  perfectNumber 6; "six is perfect")
+    (assert ! perfectNumber 7; "seven is not perfect")
+    (assert pow2 33554432; "2^25 is a power of 2")
+    (assert fib 1 == 1; "fib 1 is 1")
+    (assert fib 2 == 1; "fib 2 is 1")
+    (assert fib 3 == 2; "fib 3 is 2")
+    (assert fib 4 == 3; "fib 4 is 3")
+    (assert fib 5 == 5; "fib 5 is 5")
+    (assert fib 6 == 8; "fib 6 is 8")
+    (assert facTCO 15 == 1307674368000; "tail call optimized factorial works")
+    (assert ftco 100 == 5050; "tail call optimized fibonacci works")
+    # # nums = [2,7,11,15], target = 9
+    # (assert twosum [2 7 11 15] 9 == [0 1]; "two sum works")
+    # # Input: nums = [3,2,4], target = 6
+    # # Output: [1,2]
+    # (assert twosum [3 2 4] 6 == [1 2]; "two sum works")
+    # # Input: nums = [3,3], target = 6
+    # # Output: [0,1]
+    # (assert twosum [3 3] 6 == [0 1]; "two sum works")
 
-    ];
-    twosum = twosum [2 7 11 15] 9;  
-  }
+  ];
+}

shell.nix

@@ -1,9 +1,10 @@
-{ pkgs ? import <nixpkgs> {} }:
+{ pkgs ? import <nixpkgs> { } }:
 pkgs.mkShell {
   packages = [
     pkgs.git
-    pkgs.nixfmt
+    pkgs.nixpkgs-fmt
     pkgs.jq
     pkgs.just
+    pkgs.watch
   ];
 }