C# - O(N * 2 ^ N + 3 ^ N) Dynamic Programming + Bit Masking
csharp\npublic int MinSessions(int[] tasks, int sessionTime)\n{\n\tint mask = 1 << tasks.Length;\n\tint[] sum = new int[mask];\n\tint[] d = new int[mask];\n\tAr
```csharp\npublic int MinSessions(int[] tasks, int sessionTime)\n{\n\tint mask = 1 << tasks.Length;\n\tint[] sum = new int[mask];\n\tint[] d = new int[mask];\n\tArray.Fill(d, 1000);\n\td[0] = 0;\n\n\tfor (int i = 1; i < mask; i++)\n\t{            \n\t\tfor (int j = 0; j < tasks.Length; j++)\n\t\t{\n\t\t\tif ((i & (1 << j)) != 0)\n\t\t\t{\n\t\t\t\tsum[i] += tasks[j];\n\t\t\t}\n\t\t}\n\t}\n\n\tfor (int i = 1; i < mask; i++)\n\t{            \n\t\t// Enumerate all submasks\n\t\tfor (int j = i; j != 0; j = (j - 1) & i)\n\t\t{\n\t\t\tif (sum[j] <= sessionTime)\n\t\t\t{\n\t\t\t\td[i] = Math.Min(d[i], d[j ^ i] + 1);               \n\t\t\t}\n\t\t}\n\t}\n\n\treturn d[^1];\n}\n```
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