More robust to incorrect solutions

src/analyse-sarafu-challenge-solution.ts

@@ -8,6 +8,9 @@ const ROUNDING_MARGIN = 0.0000001;
 
 function scale(amountStr: string, filetype: string): number {
   const amount = parseFloat(amountStr);
+  if (isNaN(amount)) {
+    throw new Error(`Cannot parse float '${amountStr}'`);
+  }
   const scaledAmount = Math.round(amount * LEDGER_SCALE);
   if (Math.abs(scaledAmount - amount * LEDGER_SCALE) > ROUNDING_MARGIN) {
     throw new Error(`Ledger scale insufficient for amount in ${filetype} file: ${amountStr} -> ${amount * LEDGER_SCALE} -> ${scaledAmount}`);
@@ -57,14 +60,32 @@ async function run(): Promise<void> {
     const scaledAmount = scale(amountStr, 'solution');
     const nodes = cells.concat(cells[0]);
     // nodes would now be e.g. ['8', '5', '21', '3', 8']
-    numSolution++;
-    totalSolution += (nodes.length - 1) * scaledAmount;
+    let possible = true;
     for (let i = 0; i < nodes.length - 1; i++) {
       const edge = `${nodes[i]} ${nodes[i + 1]}`;
       if (graph[edge] < scaledAmount) {
-        throw new Error(`Netting agreement ${nodes.join(' ')} ${scaledAmount / LEDGER_SCALE} cannot be applied to edge ${edge} with balance ${graph[edge] / LEDGER_SCALE}, ${graph[edge]} < ${scaledAmount}`);
+        // console.log(`Netting agreement ${nodes.join(' ')} ${scaledAmount / LEDGER_SCALE} cannot be applied to edge ${edge} with balance ${graph[edge] / LEDGER_SCALE}, ${graph[edge]} < ${scaledAmount}`);
+        possible = false;
+      }
+      if (typeof graph[edge] === 'undefined') {
+        console.log(`Unknown edge in loop ${nodes.join('->')}, '${edge}'`);
+        // console.log(`Netting agreement ${nodes.join(' ')} ${scaledAmount / LEDGER_SCALE} cannot be applied to edge ${edge} with balance ${graph[edge] / LEDGER_SCALE}, ${graph[edge]} < ${scaledAmount}`);
+        possible = false;
+      }
+    }
+    if (possible) {
+      numSolution++;
+      totalSolution += (nodes.length - 1) * scaledAmount;
+      for (let i = 0; i < nodes.length - 1; i++) {
+        const edge = `${nodes[i]} ${nodes[i + 1]}`;
+        if (isNaN(graph[edge])) {
+          throw new Error(`have NaN balance for edge ${edge}`);
+        }
+        graph[edge] -= scaledAmount;
+        if (isNaN(graph[edge])) {
+          throw new Error(`got NaN after substracting ${scaledAmount}`);
+        }
       }
-      graph[edge] -= scaledAmount;      
     }
   });