diff --git a/.vscode/settings.json b/.vscode/settings.json
index b943dbc..8675ad5 100644
--- a/.vscode/settings.json
+++ b/.vscode/settings.json
@@ -1,3 +1,4 @@
 {
-    "deno.enable": true
+    "deno.enable": true,
+    "deno.unstable": true
 }
\ No newline at end of file
diff --git a/failures/roll1.ts b/algorithms/v1.ts
similarity index 94%
rename from failures/roll1.ts
rename to algorithms/v1.ts
index d213697..b3f6750 100644
--- a/failures/roll1.ts
+++ b/algorithms/v1.ts
@@ -8,7 +8,7 @@ import type { GachaChoice } from "../mod.ts";
 export function roll<ItemType>(
   choices: GachaChoice<ItemType>[],
 ): GachaChoice<ItemType> {
-  let filteredChoices = [];
+  const filteredChoices = [];
   for (let i = 0; i < choices.length; ++i) {
     for (let chance = choices[i].chance; chance > 0.0; --chance) {
       filteredChoices.push(i);
diff --git a/failures/roll2.ts b/algorithms/v2.ts
similarity index 91%
rename from failures/roll2.ts
rename to algorithms/v2.ts
index f53a4b5..e8dfae9 100644
--- a/failures/roll2.ts
+++ b/algorithms/v2.ts
@@ -8,7 +8,7 @@ import type { GachaChoice } from "../mod.ts";
 export function roll<ItemType>(
   choices: GachaChoice<ItemType>[],
 ): GachaChoice<ItemType> {
-  let filteredChoices = choices;
+  const filteredChoices = [];
   let total = 0.0;
     for (let i = 0; i < choices.length; ++i) {
       if (choices[i].chance > 0.0) {
@@ -16,7 +16,7 @@ export function roll<ItemType>(
         total += choices[i].chance;
       }
   }
-  let result = Math.random() * total;
+  const result = Math.random() * total;
   let going = 0.0;
   for (let i = 0; i < filteredChoices.length; ++i) {
     going += filteredChoices[i].chance;
diff --git a/algorithms/v3.ts b/algorithms/v3.ts
new file mode 100644
index 0000000..53813ec
--- /dev/null
+++ b/algorithms/v3.ts
@@ -0,0 +1,24 @@
+import type { GachaChoice } from "../mod.ts";
+
+/**
+ * Roll one from an array of gacha choices.
+ * @param {GachaChoice[]} choices - Choices to roll from.
+ * @returns {GachaChoice} Items rolled.
+ */
+export function roll<ItemType>(
+  choices: GachaChoice<ItemType>[],
+): GachaChoice<ItemType> {
+  const total = choices.reduce(
+    (acc: number, val: GachaChoice<ItemType>) => acc + val.chance,
+    0,
+  );
+  const result = Math.random() * total;
+  let going = 0.0;
+  for (let i = 0; i < choices.length; ++i) {
+    going += choices[i].chance;
+    if (result < going) {
+      return choices[i];
+    }
+  }
+  return choices[Math.floor(Math.random() * choices.length)];
+}
diff --git a/algorithms/v4.ts b/algorithms/v4.ts
new file mode 100644
index 0000000..a255000
--- /dev/null
+++ b/algorithms/v4.ts
@@ -0,0 +1,28 @@
+import type { GachaChoice } from "../mod.ts";
+
+/**
+ * Roll one from an array of gacha choices.
+ * @param {GachaChoice[]} choices - Choices to roll from.
+ * @returns {GachaChoice} Items rolled.
+ */
+export function roll<ItemType>(
+  choices: GachaChoice<ItemType>[],
+): GachaChoice<ItemType> {
+  let total = 0;
+  let i = 0;
+  while (i < choices.length) {
+    total += choices[i].chance;
+    i += 1;
+  }
+  const result = Math.random() * total;
+  let going = 0.0;
+  i = 0;
+  while (i < choices.length) {
+    going += choices[i].chance;
+    if (result < going) {
+      return choices[i];
+    }
+    i += 1;
+  }
+  return choices[Math.floor(Math.random() * choices.length)];
+}
diff --git a/algorithms/v4_sub.ts b/algorithms/v4_sub.ts
new file mode 100644
index 0000000..671450d
--- /dev/null
+++ b/algorithms/v4_sub.ts
@@ -0,0 +1,29 @@
+import type { GachaChoice } from "../mod.ts";
+
+// Dropped before release since it was slightly faster than v4.
+
+/**
+ * Roll one from an array of gacha choices.
+ * @param {GachaChoice[]} choices - Choices to roll from.
+ * @returns {GachaChoice} Items rolled.
+ */
+export function roll<ItemType>(
+  choices: GachaChoice<ItemType>[],
+): GachaChoice<ItemType> {
+  let total = 0;
+  let i = 0;
+  while (i < choices.length) {
+    total += choices[i].chance;
+    i += 1;
+  }
+  const result = Math.random() * total;
+  i -= 1;
+  while (i > -1) {
+    total -= choices[i].chance;
+    if (result > total) {
+      return choices[i];
+    }
+    i -= 1;
+  }
+  return choices[Math.floor(Math.random() * choices.length)];
+}
diff --git a/benches/100k_rolls.ts b/benches/100k_rolls.ts
new file mode 100644
index 0000000..6f0755d
--- /dev/null
+++ b/benches/100k_rolls.ts
@@ -0,0 +1,51 @@
+import { roll as roll1 } from "../algorithms/v1.ts";
+import { roll as roll2 } from "../algorithms/v2.ts";
+import { roll as roll3 } from "../algorithms/v3.ts";
+import { roll as roll4 } from "../algorithms/v4.ts";
+import { roll as roll4_sub } from "../algorithms/v4_sub.ts";
+import { GachaMachine } from "../mod.ts";
+
+import pokemon from "../testdata/pokemon.json" assert { type: "json" };
+
+const items = pokemon.slice(0, 151).map((x) => ({
+  result: x.id,
+  chance: x.tier === "legendary" ? 11 : x.tier === "mythic" ? 1 : 25,
+}));
+
+Deno.bench("nop", () => {});
+
+Deno.bench("Algorithm V1", () => {
+  for (let i = 0; i < 1e6; ++i) {
+    roll1(items);
+  }
+});
+
+Deno.bench("Algorithm V2", () => {
+  for (let i = 0; i < 1e6; ++i) {
+    roll2(items);
+  }
+});
+
+Deno.bench("Algorithm V3", () => {
+  for (let i = 0; i < 1e6; ++i) {
+    roll3(items);
+  }
+});
+
+Deno.bench("Algorithm V4 _ Sub", () => {
+  for (let i = 0; i < 1e6; ++i) {
+    roll4_sub(items);
+  }
+});
+
+Deno.bench("Algorithm V4", () => {
+  for (let i = 0; i < 1e6; ++i) {
+    roll4(items);
+  }
+});
+
+Deno.bench("Algorithm V4 in Fortuna", () => {
+  for (let i = 0; i < 1e6; ++i) {
+    GachaMachine.roll(items);
+  }
+});
diff --git a/benches/1_roll.ts b/benches/1_roll.ts
new file mode 100644
index 0000000..f17b0a6
--- /dev/null
+++ b/benches/1_roll.ts
@@ -0,0 +1,51 @@
+import { roll as roll1 } from "../algorithms/v1.ts";
+import { roll as roll2 } from "../algorithms/v2.ts";
+import { roll as roll3 } from "../algorithms/v3.ts";
+import { roll as roll4 } from "../algorithms/v4.ts";
+import { roll as roll4_sub } from "../algorithms/v4_sub.ts";
+import { GachaMachine } from "../mod.ts";
+
+import pokemon from "../testdata/pokemon.json" assert { type: "json" };
+
+const items = pokemon.slice(0, 151).map((x) => ({
+  result: x.id,
+  chance: x.tier === "legendary" ? 11 : x.tier === "mythic" ? 1 : 25,
+}));
+
+Deno.bench("nop", () => {});
+
+Deno.bench("Algorithm V1", () => {
+  for (let i = 0; i < 1e2; ++i) {
+    roll1(items);
+  }
+});
+
+Deno.bench("Algorithm V2", () => {
+  for (let i = 0; i < 1e2; ++i) {
+    roll2(items);
+  }
+});
+
+Deno.bench("Algorithm V3", () => {
+  for (let i = 0; i < 1e2; ++i) {
+    roll3(items);
+  }
+});
+
+Deno.bench("Algorithm V4 _ Sub", () => {
+  for (let i = 0; i < 1e2; ++i) {
+    roll4_sub(items);
+  }
+});
+
+Deno.bench("Algorithm V4", () => {
+  for (let i = 0; i < 1e2; ++i) {
+    roll4(items);
+  }
+});
+
+Deno.bench("Algorithm V4 in Fortuna", () => {
+  for (let i = 0; i < 1e2; ++i) {
+    GachaMachine.roll(items);
+  }
+});
diff --git a/deno.json b/deno.json
new file mode 100644
index 0000000..97d361e
--- /dev/null
+++ b/deno.json
@@ -0,0 +1,6 @@
+{
+    "tasks": {
+        "bench": "deno bench --unstable benches/100k_rolls.ts",
+        "test": "deno run --allow-hrtime test.ts"
+    }
+}
\ No newline at end of file
diff --git a/mod.js b/mod.js
index ab5ea87..9196e44 100644
--- a/mod.js
+++ b/mod.js
@@ -15,7 +15,7 @@ class GachaMachine {
         return Array.from(this.items.reduce((acc, val)=>acc.add(val.tier), new Set()).entries()).map((x)=>x[0]);
     }
     configItems(items) {
-        let newItems = items = items.sort((a, b)=>a.tier - b.tier).map((x)=>({
+        const newItems = items = items.sort((a, b)=>a.tier - b.tier).map((x)=>({
                 chance: x.chance,
                 result: x.result,
                 tier: x.tier
@@ -23,7 +23,7 @@ class GachaMachine {
         this.items = newItems;
     }
     configTiers(items) {
-        let tiers = [];
+        const tiers = [];
         const pool = this.pool;
         for(let i = 0; i < pool.length; ++i){
             tiers[pool[i]] = {
@@ -37,21 +37,17 @@ class GachaMachine {
             tiers[items[i1 - 1].tier].items += 1;
             tiers[items[i1 - 1].tier].chance += items[i1 - 1].chance;
         }
-        let tierList = [];
-        for(let i2 in tiers){
-            tierList.push(tiers[i2]);
-        }
-        this.tiers = tierList;
+        this.tiers = tiers;
     }
     get(num = 1, detailed = false, pool = this.pool) {
         if (detailed) {
-            let result = [];
+            const result = [];
             for(let i = num; i > 0; --i){
                 result.push(this.choose(pool, detailed));
             }
             return result;
         } else {
-            let result1 = [];
+            const result1 = [];
             for(let i1 = num; i1 > 0; --i1){
                 result1.push(this.choose(pool));
             }
@@ -59,22 +55,29 @@ class GachaMachine {
         }
     }
     choose(pool = this.pool, detailed) {
-        let tier = GachaMachine.roll(this.tiers.filter((x)=>pool.includes(x.tier)).map((x)=>({
+        const tier = GachaMachine.roll(this.tiers.filter((x)=>pool.includes(x.tier)).map((x)=>({
                 chance: x.chance,
                 result: x.tier
             })));
         const result = GachaMachine.roll(this.items.filter((x)=>x.tier == tier.result));
         return detailed ? result : result.result;
     }
-    static roll(choices) {
-        const total = choices.reduce((acc, val)=>acc + val.chance, 0);
-        let result = Math.random() * total;
+    static roll(choices, totalChance) {
+        let total = totalChance || 0;
+        let i = 0;
+        while(i < choices.length){
+            total += choices[i].chance;
+            i += 1;
+        }
+        const result = Math.random() * total;
         let going = 0.0;
-        for(let i = 0; i < choices.length; ++i){
+        i = 0;
+        while(i < choices.length){
             going += choices[i].chance;
             if (result < going) {
                 return choices[i];
             }
+            i += 1;
         }
         return choices[Math.floor(Math.random() * choices.length)];
     }
diff --git a/mod.ts b/mod.ts
index f06bb43..f71b74e 100644
--- a/mod.ts
+++ b/mod.ts
@@ -141,17 +141,21 @@ export class GachaMachine<ItemType> {
     choices: GachaChoice<ItemType>[],
     totalChance?: number,
   ): GachaChoice<ItemType> {
-    const total = totalChance || choices.reduce(
-      (acc: number, val: GachaChoice<ItemType>) => acc + val.chance,
-      0,
-    );
+    let total = totalChance || 0;
+    let i = 0;
+    while (i < choices.length) {
+      total += choices[i].chance;
+      i += 1;
+    }
     const result = Math.random() * total;
     let going = 0.0;
-    for (let i = 0; i < choices.length; ++i) {
+    i = 0;
+    while (i < choices.length) {
       going += choices[i].chance;
       if (result < going) {
         return choices[i];
       }
+      i += 1;
     }
     return choices[Math.floor(Math.random() * choices.length)];
   }
diff --git a/test.ts b/test.ts
index 0fa6806..53bfb20 100644
--- a/test.ts
+++ b/test.ts
@@ -24,6 +24,7 @@ const items = pokemon.slice(0, 151).map((x) => ({
   weight: x.tier === "legendary" ? 10 : x.tier === "mythic" ? 1 : 25,
 }));
 
+
 const timeConfig = performance.now();
 
 const machine = new GachaMachine(items);
@@ -91,3 +92,4 @@ console.log(
     ["s", "ms", "us", "ns"],
   ),
 );
+// console.log(items.map(x => `GachaChoice {${JSON.stringify(x)}}`).join(",\n"))