Simplify example generation

oss-apps · Feb 18, 2025 · 444952c · 444952c
1 parent 1f9e37f
commit 444952c
Showing 1 changed file with 109 additions and 110 deletions.
diff --git a/src/lib/simplify.test.ts b/src/lib/simplify.test.ts
@@ -2,6 +2,12 @@ import { GroupBalance } from '@prisma/client';
 import { simplifyDebts } from './simplify';
 import { addHours } from 'date-fns';
 
+type MinimalEdge = {
+  userOne: number;
+  userTwo: number;
+  amount: number;
+};
+
 const sortByIds = (a: GroupBalance, b: GroupBalance) => {
   if (a.userId === b.userId) {
     return a.firendId - b.firendId;
@@ -11,11 +17,7 @@ const sortByIds = (a: GroupBalance, b: GroupBalance) => {
 
 let dateCounter = 0;
 
-const edgeToGroupBalance = (edge: {
-  userOne: number;
-  userTwo: number;
-  amount: number;
-}): [GroupBalance, GroupBalance] => {
+const edgeToGroupBalance = (edge: MinimalEdge): [GroupBalance, GroupBalance] => {
   const base = {
     groupId: 0,
     currency: 'USD',
@@ -37,111 +39,108 @@ const edgeToGroupBalance = (edge: {
   ];
 };
 
+const padWithZeroBalances = (balances: GroupBalance[], userCount: number): GroupBalance[] => {
+  const result = [...balances];
+  for (let userId = 0; userId < userCount; userId++) {
+    for (let friendId = userId + 1; friendId < userCount; friendId++) {
+      const found = balances.find(
+        (balance) => balance.userId === userId && balance.firendId === friendId,
+      );
+
+      if (!found) {
+        result.push(...edgeToGroupBalance({ userOne: userId, userTwo: friendId, amount: 0 }));
+      }
+    }
+  }
+  return result;
+};
+
+const getFullBalanceGraph = (edges: MinimalEdge[], userCount: number): GroupBalance[] => {
+  return padWithZeroBalances(edges.flatMap(edgeToGroupBalance), userCount).toSorted(sortByIds);
+};
+
 // taken from https://www.geeksforgeeks.org/minimize-cash-flow-among-given-set-friends-borrowed-money/
-const smallGraph: GroupBalance[] = [
-  { userOne: 0, userTwo: 1, amount: 10 },
-  { userOne: 1, userTwo: 2, amount: 50 },
-  { userOne: 2, userTwo: 0, amount: -20 },
-].flatMap(edgeToGroupBalance);
-
-const smallGraphResult: GroupBalance[] = [
-  { userOne: 0, userTwo: 1, amount: 0 },
-  { userOne: 1, userTwo: 2, amount: 40 },
-  { userOne: 2, userTwo: 0, amount: -30 },
-]
-  .flatMap(edgeToGroupBalance)
-  .map((resultBalance, idx) => ({
-    ...resultBalance,
-    updatedAt: smallGraph[idx]!.updatedAt,
-  }))
-  .toSorted(sortByIds);
+const smallGraph: GroupBalance[] = getFullBalanceGraph(
+  [
+    { userOne: 0, userTwo: 1, amount: 10 },
+    { userOne: 1, userTwo: 2, amount: 50 },
+    { userOne: 2, userTwo: 0, amount: -20 },
+  ],
+  3,
+);
+
+const smallGraphResult: GroupBalance[] = getFullBalanceGraph(
+  [
+    { userOne: 1, userTwo: 2, amount: 40 },
+    { userOne: 2, userTwo: 0, amount: -30 },
+  ],
+  3,
+).map((resultBalance, idx) => ({
+  ...resultBalance,
+  updatedAt: smallGraph[idx]!.updatedAt,
+}));
 
 // taken from https://medium.com/@mithunmk93/algorithm-behind-splitwises-debt-simplification-feature-8ac485e97688
-const largeGraph: GroupBalance[] = [
-  { userOne: 0, userTwo: 1, amount: 0 },
-  { userOne: 0, userTwo: 2, amount: 0 },
-  { userOne: 0, userTwo: 3, amount: 0 },
-  { userOne: 0, userTwo: 4, amount: 0 },
-  { userOne: 0, userTwo: 5, amount: 0 },
-  { userOne: 0, userTwo: 6, amount: 0 },
-
-  { userOne: 1, userTwo: 2, amount: 40 },
-  { userOne: 1, userTwo: 3, amount: 0 },
-  { userOne: 1, userTwo: 4, amount: 0 },
-  { userOne: 1, userTwo: 5, amount: -10 },
-  { userOne: 1, userTwo: 6, amount: -30 },
-
-  { userOne: 2, userTwo: 3, amount: 20 },
-  { userOne: 2, userTwo: 4, amount: 0 },
-  { userOne: 2, userTwo: 5, amount: -30 },
-  { userOne: 2, userTwo: 6, amount: 0 },
-
-  { userOne: 3, userTwo: 4, amount: 50 },
-  { userOne: 3, userTwo: 5, amount: -10 },
-  { userOne: 3, userTwo: 6, amount: -10 },
-
-  { userOne: 4, userTwo: 5, amount: -10 },
-  { userOne: 4, userTwo: 6, amount: 0 },
-
-  { userOne: 5, userTwo: 6, amount: 0 },
-].flatMap(edgeToGroupBalance);
-
-const largeGraphResult: GroupBalance[] = [
-  { userOne: 0, userTwo: 1, amount: 0 },
-  { userOne: 0, userTwo: 2, amount: 0 },
-  { userOne: 0, userTwo: 3, amount: 0 },
-  { userOne: 0, userTwo: 4, amount: 0 },
-  { userOne: 0, userTwo: 5, amount: 0 },
-  { userOne: 0, userTwo: 6, amount: 0 },
-
-  { userOne: 1, userTwo: 2, amount: 10 },
-  { userOne: 1, userTwo: 3, amount: 0 },
-  { userOne: 1, userTwo: 4, amount: 0 },
-  { userOne: 1, userTwo: 5, amount: 0 },
-  { userOne: 1, userTwo: 6, amount: -10 },
-
-  { userOne: 2, userTwo: 3, amount: 0 },
-  { userOne: 2, userTwo: 4, amount: 0 },
-  { userOne: 2, userTwo: 5, amount: -40 },
-  { userOne: 2, userTwo: 6, amount: 0 },
-
-  { userOne: 3, userTwo: 4, amount: 40 },
-  { userOne: 3, userTwo: 5, amount: 0 },
-  { userOne: 3, userTwo: 6, amount: -30 },
-
-  { userOne: 4, userTwo: 5, amount: -20 },
-  { userOne: 4, userTwo: 6, amount: 0 },
-
-  { userOne: 5, userTwo: 6, amount: 0 },
-]
-  .flatMap(edgeToGroupBalance)
-  .map((resultBalance, idx) => ({
-    ...resultBalance,
-    updatedAt: largeGraph[idx]!.updatedAt,
-  }))
-  .toSorted(sortByIds);
-
-const largeGraph2: GroupBalance[] = [
-  { userOne: 0, userTwo: 1, amount: 8957.95 },
-  { userOne: 0, userTwo: 2, amount: 3280.43 },
-  { userOne: 0, userTwo: 3, amount: -1746.24 },
-  { userOne: 0, userTwo: 4, amount: 50.35 },
-  { userOne: 0, userTwo: 5, amount: -814.16 },
-
-  { userOne: 1, userTwo: 2, amount: -3245.6 },
-  { userOne: 1, userTwo: 3, amount: -115.02 },
-  { userOne: 1, userTwo: 4, amount: 1261.15 },
-  { userOne: 1, userTwo: 5, amount: 833.33 },
-
-  { userOne: 2, userTwo: 3, amount: -5191.67 },
-  { userOne: 2, userTwo: 4, amount: -4000.5 },
-  { userOne: 2, userTwo: 5, amount: -233.34 },
-
-  { userOne: 3, userTwo: 4, amount: 1572.84 },
-  { userOne: 3, userTwo: 5, amount: 158.33 },
-
-  { userOne: 4, userTwo: 5, amount: 129.16 },
-].flatMap(edgeToGroupBalance);
+const largeGraph: GroupBalance[] = getFullBalanceGraph(
+  [
+    { userOne: 1, userTwo: 2, amount: 40 },
+    { userOne: 1, userTwo: 5, amount: -10 },
+    { userOne: 1, userTwo: 6, amount: -30 },
+
+    { userOne: 2, userTwo: 3, amount: 20 },
+    { userOne: 2, userTwo: 5, amount: -30 },
+
+    { userOne: 3, userTwo: 4, amount: 50 },
+    { userOne: 3, userTwo: 5, amount: -10 },
+    { userOne: 3, userTwo: 6, amount: -10 },
+
+    { userOne: 4, userTwo: 5, amount: -10 },
+  ],
+  7,
+);
+
+const largeGraphResult: GroupBalance[] = getFullBalanceGraph(
+  [
+    { userOne: 1, userTwo: 2, amount: 10 },
+    { userOne: 1, userTwo: 6, amount: -10 },
+
+    { userOne: 2, userTwo: 5, amount: -40 },
+
+    { userOne: 3, userTwo: 4, amount: 40 },
+    { userOne: 3, userTwo: 6, amount: -30 },
+
+    { userOne: 4, userTwo: 5, amount: -20 },
+  ],
+  7,
+).map((resultBalance, idx) => ({
+  ...resultBalance,
+  updatedAt: largeGraph[idx]!.updatedAt,
+}));
+
+const largeGraph2: GroupBalance[] = getFullBalanceGraph(
+  [
+    { userOne: 0, userTwo: 1, amount: 8957.95 },
+    { userOne: 0, userTwo: 2, amount: 3280.43 },
+    { userOne: 0, userTwo: 3, amount: -1746.24 },
+    { userOne: 0, userTwo: 4, amount: 50.35 },
+    { userOne: 0, userTwo: 5, amount: -814.16 },
+
+    { userOne: 1, userTwo: 2, amount: -3245.6 },
+    { userOne: 1, userTwo: 3, amount: -115.02 },
+    { userOne: 1, userTwo: 4, amount: 1261.15 },
+    { userOne: 1, userTwo: 5, amount: 833.33 },
+
+    { userOne: 2, userTwo: 3, amount: -5191.67 },
+    { userOne: 2, userTwo: 4, amount: -4000.5 },
+    { userOne: 2, userTwo: 5, amount: -233.34 },
+
+    { userOne: 3, userTwo: 4, amount: 1572.84 },
+    { userOne: 3, userTwo: 5, amount: 158.33 },
+
+    { userOne: 4, userTwo: 5, amount: 129.16 },
+  ],
+  6,
+);
 
 describe('simplifyDebts', () => {
   it('simplifies small graph', () => {
@@ -161,16 +160,16 @@ describe('simplifyDebts', () => {
 
   it.each([{ graph: smallGraph }, { graph: largeGraph }, { graph: largeGraph2 }])(
     'preserves the total balance per user',
-    () => {
-      const startingBalances = largeGraph.reduce(
+    ({ graph }) => {
+      const startingBalances = graph.reduce(
         (acc, balance) => {
           acc[balance.userId] = (acc[balance.userId] ?? 0) + balance.amount;
           return acc;
         },
         {} as Record<number, number>,
       );
 
-      const userBalances = simplifyDebts(largeGraph).reduce(
+      const userBalances = simplifyDebts(graph).reduce(
         (acc, balance) => {
           acc[balance.userId] = (acc[balance.userId] ?? 0) + balance.amount;
           return acc;