diff --git a/code_study/Baekjoon/ts/30805.ts b/code_study/Baekjoon/ts/30805.ts
new file mode 100644
index 0000000..5300e09
--- /dev/null
+++ b/code_study/Baekjoon/ts/30805.ts
@@ -0,0 +1,45 @@
+export {};
+
+type pair = [number, number]; // [value, index]
+
+const input: string[] = require("fs").readFileSync(0).toString().trim().split('\n');
+const [N, M]: number[] = [Number(input[0]), Number(input[2])];
+let A: number[] = input[1].split(' ').map(Number);
+let B: number[] = input[3].split(' ').map(Number);
+
+const comparator = (a: pair, b: pair) => {
+    if(a[0] === b[0]) return a[1] - b[1];
+    return b[0]-a[0];
+};
+
+let pairA: pair[] = A.map((v,i)=>[v,i]);
+let pairB: pair[] = B.map((v,i)=>[v,i]);
+
+pairA.sort(comparator);
+pairB.sort(comparator);
+
+let subsequence: number[] = [];
+let limitA = -1, limitB = -1;
+let idxA = 0, idxB = 0;
+
+while(idxA < N && idxB < M) {
+    const [valA, posA]: number[] = pairA[idxA];
+    const [valB, posB]: number[] = pairB[idxB];
+
+    if(valA===valB) {
+        if(posA > limitA && posB > limitB) {
+            subsequence.push(valA);
+            limitA = posA;
+            limitB = posB;
+            idxA++;
+            idxB++;
+        }
+        else if(posA <= limitA) idxA++;
+        else idxB++;
+    }
+    else if(valA > valB) idxA++;
+    else idxB++;
+}
+
+console.log(subsequence.length);
+if (subsequence.length !== 0) console.log(...subsequence);