feat: implemented kmpseach algo

Author: PresenceOP-Coder

src/algorithms/dynamic-programming/kmpSearchAlgo.js

@@ -0,0 +1,161 @@
+export function computeLPSSteps(pattern) {
+    const m = pattern.length;
+    const lps = Array(m).fill(0);
+    const steps = [];
+    let len = 0; 
+    let i = 1;
+  
+    steps.push({
+      lps: [...lps],
+      i: 1,
+      len: 0,
+      message: "Initializing LPS table. lps[0] is always 0. Starting from i = 1.",
+      highlight: { i: 1, len: 0, lps: -1 },
+    });
+  
+    while (i < m) {
+      steps.push({
+        lps: [...lps],
+        i: i,
+        len: len,
+        message: `Comparing pattern[${i}] ('${pattern[i]}') and pattern[${len}] ('${pattern[len]}').`,
+        highlight: { i: i, len: len, lps: -1 },
+      });
+  
+      if (pattern[i] === pattern[len]) {
+        len++;
+        lps[i] = len;
+        steps.push({
+          lps: [...lps],
+          i: i,
+          len: len,
+          message: `Match! lps[${i}] = ${len}. Increment i and len.`,
+          highlight: { i: i, len: len, lps: i, state: 'match' },
+        });
+        i++;
+      } else { 
+        if (len !== 0) {
+          len = lps[len - 1];
+          steps.push({
+            lps: [...lps],
+            i: i,
+            len: len,
+            message: `Mismatch. Falling back: len = lps[${len - 1}] = ${len}.`,
+            highlight: { i: i, len: len, lps: -1, state: 'mismatch' },
+          });
+        } else {
+          lps[i] = 0;
+          steps.push({
+            lps: [...lps],
+            i: i,
+            len: len,
+            message: `Mismatch. No fallback. lps[${i}] = 0. Increment i.`,
+            highlight: { i: i, len: len, lps: i, state: 'mismatch' },
+          });
+          i++;
+        }
+      }
+    }
+  
+    steps.push({
+      lps: [...lps],
+      i: m,
+      len: len,
+      message: "LPS table computation complete.",
+      highlight: { i: m, len: len, lps: -1, state: 'done' },
+    });
+    return { steps, lpsTable: lps };
+  }
+  
+  export function kmpSearchSteps(text, pattern, lps) {
+    const n = text.length;
+    const m = pattern.length;
+    const steps = [];
+    const matches = [];
+    let i = 0; 
+    let j = 0; 
+  
+    steps.push({
+      i: i,
+      j: j,
+      matches: [...matches],
+      message: "Starting KMP search. i = 0 (text), j = 0 (pattern).",
+      highlight: { i: 0, j: 0, state: 'idle' }
+    });
+  
+    while (i < n) {
+      if (j === 0) {
+        steps.push({
+          i: i,
+          j: j,
+          matches: [...matches],
+          message: `Comparing text[${i}] ('${text[i]}') and pattern[${j}] ('${pattern[j]}').`,
+          highlight: { i: i, j: j, state: 'compare' }
+        });
+      } else {
+           steps.push({
+          i: i,
+          j: j,
+          matches: [...matches],
+          message: `Comparing text[${i}] ('${text[i]}') and pattern[${j}] ('${pattern[j]}').`,
+          highlight: { i: i, j: j, state: 'compare' }
+        });
+      }
+  
+  
+      if (pattern[j] === text[i]) {
+        i++;
+        j++;
+      }
+  
+      if (j === m) {
+        const matchIndex = i - j;
+        matches.push(matchIndex);
+        steps.push({
+          i: i,
+          j: j,
+          matches: [...matches],
+          message: `PATTERN FOUND! at index ${matchIndex}.`,
+          highlight: { i: i, j: j, state: 'match', matchIndex: matchIndex }
+        });
+        j = lps[j - 1];
+         steps.push({
+          i: i,
+          j: j,
+          matches: [...matches],
+          message: `Jumping pattern pointer using LPS: j = lps[${m - 1}] = ${j}.`,
+          highlight: { i: i, j: j, state: 'jump' }
+        });
+      } else if (i < n && pattern[j] !== text[i]) {
+        if (j !== 0) {
+          j = lps[j - 1];
+          steps.push({
+            i: i,
+            j: j,
+            matches: [...matches],
+            message: `Mismatch. Jumping pattern pointer using LPS: j = lps[${j - 1}] = ${j}.`,
+            highlight: { i: i, j: j, state: 'jump' }
+          });
+        } else {
+          i++;
+           steps.push({
+            i: i,
+            j: j,
+            matches: [...matches],
+            message: `Mismatch at j=0. Incrementing text pointer i to ${i}.`,
+            highlight: { i: i, j: j, state: 'mismatch' }
+          });
+        }
+      }
+    }
+  
+    steps.push({
+      i: n,
+      j: j,
+      matches: [...matches],
+      message: `Search complete. ${matches.length} match(es) found.`,
+      highlight: { i: n, j: j, state: 'done' }
+    });
+  
+    return { steps, matches };
+  }