sum3val

cses/sortingsearching/sum3val/brute.cpp

@@ -0,0 +1,25 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+vector<int> a(5000);
+
+int main()
+{
+  int n, x;
+  cin >> n >> x;
+
+  for (int i = 0; i < n; ++i)
+    cin >> a[i];
+
+  for (int i = 2; i < n; ++i)
+    for (int j = 1; j < i; ++j)
+      for (int k = 0; k < j; ++k)
+        if (a[i] + a[j] + a[k] == x)
+        {
+          cout << i + 1 << ' ' << j + 1 << ' ' << k + 1 << '\n';
+          return 0;
+        }
+
+  cout << "IMPOSSIBLE\n";
+  return 0;
+}

cses/sortingsearching/sum3val/correct.out

@@ -0,0 +1 @@
+8 7 3

cses/sortingsearching/sum3val/incorrect.out

@@ -0,0 +1 @@
+IMPOSSIBLE

cses/sortingsearching/sum3val/input.in

@@ -0,0 +1,2 @@
+9 71
+5 10 48 49 31 43 16 7 19

cses/sortingsearching/sum3val/stress.py

@@ -0,0 +1,45 @@
+from random import randint
+from subprocess import run, PIPE
+
+def gen_input():
+  n = randint(1, 10)
+  x = randint(1, 100)
+  vals = [str(randint(1, 100)) for _ in range(n)]
+
+  return f"{n} {x}\n{' '.join(vals)}\n"
+
+def stress():
+  generated = gen_input()
+  my_solution = run(["./sum3val"], stdout=PIPE, input=generated, encoding="ascii")
+  correct_solution = run(["./brute"], stdout=PIPE, input=generated, encoding="ascii")
+
+  print(my_solution.stdout.split(" "), correct_solution.stdout.split(" "))
+  correct = (my_solution.stdout == correct_solution.stdout == "IMPOSSIBLE") or \
+              (set(map(str.strip, my_solution.stdout.split(" "))) == 
+               set(map(str.strip, correct_solution.stdout.split(" "))))
+
+  if not correct:
+    with open("input.in", "w") as fin:
+      fin.write(generated)
+
+    with open("correct.out", "w") as fout:
+      fout.write(correct_solution.stdout)
+
+    with open("incorrect.out", "w") as fout:
+      fout.write(my_solution.stdout)
+
+    return False
+
+  return True
+
+
+i = 1
+while True:
+  result = stress()
+  if result:
+    print(f"Success on test case {i}")
+  else:
+    print(f"Found wrong test case ({i})!")
+    break
+
+  i += 1

cses/sortingsearching/sum3val/sum3val.cpp

@@ -0,0 +1,45 @@
+// https://cses.fi/problemset/task/1641
+
+// TODO
+
+#include <bits/stdc++.h>
+using namespace std;
+
+#define MAX_N 5000
+
+vector<pair<int, int>> a(MAX_N);
+
+int main()
+{
+  int n, x;
+  cin >> n >> x;
+
+  for (int i = 0; i < n; ++i)
+    cin >> a[i].first, a[i].second = i + 1;
+
+  sort(a.begin(), a.begin() + n, [](const auto &a, const auto &b)
+       { return a.first < b.first; });
+
+  for (int i = 0; i < n; ++i)
+  {
+    const int need = x - a[i].first;
+    int l = 0, r = n - 1;
+    while (l != r)
+    {
+      if (l != i && r != i && a[l].first + a[r].first == need)
+      {
+        cout << a[i].second << ' ' << a[l].second << ' ' << a[r].second << '\n';
+        return 0;
+      }
+
+      if (a[l].first + a[r].first < need)
+        ++l;
+      else
+        --r;
+    }
+  }
+
+  cout << "IMPOSSIBLE\n";
+
+  return 0;
+}