@@ -0,0 +1,45 @@
+const lengthAfterTransformations = (s, t, nums) => {
+const MOD = 1000000007n
+const ALPHA = 26
+const codeA = 'a'.charCodeAt(0)
+
+const initMatrix = () =>
+Array(ALPHA)
+.fill()
+.map(() => Array(ALPHA).fill(0n))
+
+const base = initMatrix()
+nums.forEach((count, i) => {
+for (let k = 1; k <= count; k++) {
+base[i][(i + k) % ALPHA] += 1n
+}
+})
+
+let counts = Array(ALPHA).fill(0n)
+
+for (const ch of s) {
+counts[ch.charCodeAt(0) - codeA] += 1n
+}
+
+const mulMatrix = (A, B) =>
+A.map((row, i) => row.map((_, j) => row.reduce((sum, v, k) => (sum + v * B[k][j]) % MOD, 0n)))
+
+const mulVector = (vec, M) =>
+Array(ALPHA)
+.fill()
+.map((_, j) => vec.reduce((sum, vi, i) => (sum + vi * M[i][j]) % MOD, 0n))
+
+let powerMat = base
+let exp = t
+
+while (exp > 0) {
+if (exp & 1) {
+counts = mulVector(counts, powerMat)
+}
+powerMat = mulMatrix(powerMat, powerMat)
+exp >>= 1
+}
+
+const result = counts.reduce((sum, cnt) => (sum + cnt) % MOD, 0n)
+return Number(result)
+}