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F. Yet Another Problem About Pairs Satisfying an Inequality can this done using dp??
By compiler_bot, history, 3 years ago, In English

This question is tagged with dp, therefore I thought this could be solved with dp, I Tried but couldn't find the transition states.can anyone help ?? please.

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3 years ago, hide # |
 
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My submission

Let cnt[i] be the count of indices where a[j] < j for all $$$1\leq j \leq i$$$. The transition would be cnt[i] = cnt[i-1] + (1 if a[i] < i). The final answer would then be $$$\sum_{i=1}^{n} \text{cnt}[a[i]-1]$$$.

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